Proponente/Relatore RFX: L. Giudicotti
Relatore Accademico: M. Agostini
Capogruppo: L. Carraro
Responsabile di Programma: T. Bolzonella
Tipologia: Modelling, Teorica, Sperimentale, Compilativa
Abstract:
Thomson scattering (TS) of laser light is a well known diagnostic technique for the measurement of spatial profiles of electron temperature Te and electron density ne in fusion plasmas. For the new italian experiment DTT (Divertor Tokamak Test) a TS system based on the LIDAR approach is being considered. In LIDAR TS, a high power laser pulse with a time duration of ~150 ns (corresponding to a spatial extension of ~4.5 cm) is sent into the plasma and the scattering signal is collected from the back. The spatial profile of Te and ne is determined measuring the time evolution of the scattering light. This technique poses considerable experimental challenges and requires the most advanced solutions in terms of laser and detector technology. In the framework of this activity the student will carry out laboratory tests for the complete characterization of very high speed microchannel plate photomultipliers (MCP-PMTs), comparing their characteristics of sensibility, speed of response and linearity. Then, the student will optionally use the measured data for the development of a model of the DTT LIDAR TS system, useful for simulating and optimizing the performance of the diagnostic system.
Competenze richieste:
Basic experience of laboratory work and programming (in any language). Knowledge of laser and solid state physics are welcome but not mandatory.
Tesi assegnata a:
Proponente/Relatore RFX: P.Franz
Relatore accademico: F.Sattin
Capogruppo RFX: L.Carraro
Responsabile di Programma RFX: L. Marrelli
Tipologia: Modelling, Teorica, Sperimentale, Compilativa
Abstract:
The temperature profiles of electrons in quasi-single helical (QSH) states in RFX-Mod present clear transport barriers. The study of these profiles is mainly conducted using Thomson scattering, which has a time resolution limited by laser pulse repetition frequency (100 Hz). A two-foil SXR spectrometer allowed this study to be extended. Temperature profiles can be measured up to a frequency of a few kHz, and the entire temporal evolution of the electron temperature during a QSH cycle can be determined. A mapping technique, originally developed for Thomson temperature profiles, has also been applied to profiles measured with SXR diagnostics. In particular, the temperature gradients linked to the presence of transport barriers are reconstructed and analyzed in a helical reference system, consistently with the equilibrium of the underlying plasma. A clear difference in the behavior of the temperature gradient is observed between the ascending phase of the QSH and the saturated (or flattop) phase.
The proposed thesis subject is the statistical application of the method to the available QSH database. More specifically, analysis of the greatest number of Te profiles during the QSH phases, choosing the cases in which both types of profiles are available (from the TS and the SXR), will be performed. The target is the establishment and characterization of three types of electron temperature profiles: MH (without transport barriers), DAx (transport barrier with two magnetic axes) and SHAx (transport barrier with a single magnetic axis). Moreover, the study will allow to “calibrate” the Te profile from the SXR to the TS profile, which is much more resolved in space. The work will then extend the Te from SXR data analysis to follow the temporal evolution of Te profiles and gradients with a resolution of a few kHz.
The adaptation/ development/optimization of the already available software tools, will be an important element of the proposed work.
Competenze necessarie per svolgere con successo la tesi:
Good aptitude to data analysis work. Knowledge of computer language programming (Python, IDL) required.
Tesi assegnata a: Alessandro Paronetto
Relatore RFX: B. Zaniol
Relatore Accademico: M. Agostini
Capogruppo: L. Carraro
Responsabile di Programma: D. Marcuzzi
Tipologia: Sperimentale, Teorica, Data Analysis, Compilativa
Abstract:
Spider is the prototype of negative ion source for ITER neutral beams, in development at Consorzio RFX, Padova. To help optimising the negative ion production, Spider is equipped with a full set of optical diagnostics that analyses the EM radiation spontaneously emitted by the plasma inside the source. Part of the optical diagnostics are spectroscopy based and they produce wavelength resolved spectra in the range between 300 nm to 900 nm. By analyzing these spectra, it is possible to study the relation between source plasma and negative ion production. Emission models will be also used to gather information on plasma density and temperature. Aim of the thesis is to characterize SPIDER optical emissions against the variation of the experimental conditions.
Competenze richieste: Programmazione di base
Tesi assegnata a: Elena Albano
Proponente/Relatore RFX: M. Zuin
Relatore Accademico: M. Zuin
Capogruppo: M. Zuin
Responsabile di Programma: L. Marrelli
Tipologia: Sperimentale, Teorica, Data Analysis, Compilativa
Abstract:
The thesis aims at the investigation of the properties of magnetic fluctuations measured at the edge of the RFX-mod experiment. In particular, the focus of the analysis will be on the role of the magnetic equilibrium in determining the spectral properties, mainly in terms of frequency and wavenumbers, and the nature of small-scale instabilities in Reversed-Field Pinch plasmas. Signals coming from a distributed system of in-vessel sensors, measuring the time variation of the magnetic field at the very edge of the plasma with high time (of the order of 1 microsecond) and space (of few centimeters) resolution, will be analyzed.
Part of the work will be devoted to the selection, within the whole RFX-mod database, of plasma discharges characterized by active variations of the plasma equilibrium in the form of the so-called Oscillating Poloidal Current Drive (OPCD) operations, based on an externally controlled periodic variation of the applied edge toroidal magnetic field.
The activity will be mainly performed inside the laboratories of Consorzio RFX, Area CNR, Padova.
Competenze richieste (se necessarie): Basic plasma physics knowledge
Tesi assegnata a: Simone Paulon
Proponente/Relatore RFX: M. Ugoletti
Relatore Accademico: M. Agostini
Capogruppo: L. Carraro
Responsabile di Programma: TBD
Tipologia: Sperimentale, Teorica, Analisi dati, Compilativa
Abstract:
Lo studio del bordo del plasma è cruciale negli esperimenti di fusione nucleare, poiché influenza sia la stabilità del plasma principale, sia le interazioni con le pareti del reattore, determinando l’efficienza globale del sistema. Tra le varie diagnostiche di bordo, il Thermal Helium Beam (THB) è una diagnostica molto importante perché permette di misurare simultaneamente sia la densità e la temperatura elettronica che le loro relative fluttuazioni e instabilità. Il THB che è stato installato sul tokamak TCV, per la prima volta, misura anche il riassorbimento dei fotoni dell’He, informazione fondamentale per la corretta stima dei parametri del plasma.
Si propone un lavoro di tesi di analisi dei dati sperimentali raccolti a TCV, con l’obiettivo di definire uno spazio operazionale che correli i parametri del plasma con l’assorbimento della radiazione e la quantità di elio iniettata per effettuare la misura. Attraverso lo studio e l’elaborazione dei dati, si cercherà di identificare le condizioni ottimali di funzionamento della diagnostica, migliorandone sensibilità e affidabilità. Questo progetto permetterà di approfondire i processi fisici che avvengono nel plasma edge e di acquisire competenze nell’analisi di dati sperimentali e nello sviluppo di modelli per la diagnostica di plasmi ad alta temperatura.
Competenze richieste (se necessarie): Programmazione di base
Tesi assegnata a: Marilena Santarossa
Proponente RFX: M.Gobbin /I.Predebon
Relatore Accademico: F.Sattin
Capogruppo: D. Terranova
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
In fusion plasmas, impurities refer to elements other than the primary working gas. These
impurities can arise from various sources, such as plasma-facing components, external
injections, or residual gases. Their presence profoundly influences the plasma’s behavior,
affecting energy confinement, radiation losses, and overall stability. Consequently,
understanding and controlling impurity transport is essential for enhancing plasma
performance.
Experiments conducted on the reversed field pinch device RFX-mod have revealed that
impurities exhibit an outward flux, preventing them from penetrating the plasma’s inner core.
However, these observations cannot be fully explained by first-principles theoretical models.
To address this issue, numerical simulations based on the Hamiltonian guiding-centre code
ORBIT, combined with post-processing analysis tools, could provide a valuable
complementary perspective. The thesis activity will therefore mainly consist in using this
numerical framework to analyze the transport properties of several impurity species commonly
found in the RFX-mod experiment, at different levels of magnetic chaos, also accounting for
collisions and for the radial electric field arising due to ambipolarity violation. Particular
attention will be devoted to the range of experimental parameters foreseen in the next RFX-
mod2 device, which will soon start operation.
Tesi assegnata a: Federico Cossettini
Relatore RFX: P. Agostinetti
Relatore accademico: E. Sartori
Capogruppo RFX: A. Rizzolo
Responsabile di Programma RFX: D. Marcuzzi
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
La sorgente di ioni negativi SPIDER, prototipo della sorgente dell’iniettore di neutri per ITER, nel 2026 dovrà raggiungere le condizioni nominali di operazione in termini di corrente totale, energia ed uniformità del fascio. I recenti risultati ottenuti con ¼ della sorgente hanno indicato una inattesa disuniformità; questa consiste in una diversa corrente associata con i singoli fascetti che compongono il fascio di particelle (1280 in tutto). Questo risultato inatteso potrebbe originarsi o nella fase di accelerazione, o può essere già presente nel plasma da cui il fascio di ioni viene estratto. E’ necessario identificare le possibili cause e, in vista della prossima operazione, rimuovere le incognite relative a possibili errori di allineamento.
Negli acceleratori elettrostatici di grande corrente, il fascio di ioni si realizza attraverso multiple aperture in ciascun elettrodo (griglia). Le aperture di ciascun elettrodo devono essere allineate all’interno di una tolleranza molto stretta, dell’ordine di decimi di millimetro. Uno spostamento trasversale dei fori rispetto all’asse nominale fa si che il fascio di ioni attraversi la lente elettrostatica fuori asse, causando una deflessione media delle traiettorie. In aggiunta, anche la distanza tra gli elettrodi gioca un ruolo fondamentale nella definizione dell’ottica del fascio, dato che influenza direttamente il campo elettrico assiale. Le condizioni di allineamento nominale devono essere garantite quando gli elettrodi lavorano a caldo: ad esempio, il primo elettrodo dell’acceleratore, affacciato al plasma, è mantenuto ad una temperatura nominale di 150°C, mentre gli altri elettrodi lavorano circa a temperatura ambiente.
Questo lavoro di tesi si propone di progettare e realizzare un sistema di misura per rilevare gli allineamenti tra le griglie dell’acceleratore, e di ottenere gli spostamenti relativi e gli allineamenti in delle prove dedicate, scaldando gli elettrodi alle temperature nominali di lavoro. Le deformazioni a caldo possono essere rilevate solamente quando l’intero acceleratore è riassemblato, ma solo se si predispongono dei puntatori/supporti dedicati e poi si organizza la misura, impiegando laser tracker ed altre soluzioni. Il lavoro di tesi sarà integrato nelle attività del gruppo di lavoro. La definizione della strategia di prova, della procedura di misura, la progettazione e realizzazione dei componenti necessari, i rilievi e la preparazione della documentazione saranno parte del lavoro di tesi. Secondo il piano attuale, la misura dovrà essere completata per marzo 2026.
Tesi assegnata a: Marta Romanello
Proponente/Relatore RFX: T. Patton
Relatore accademico: E. Sartori
Capogruppo RFX: M. Brombin
Responsabile di Programma RFX: D. Marcuzzi
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
La sorgente di ioni negativi SPIDER, prototipo della sorgente dell’iniettore di neutri per ITER, nel 2026 dovrà raggiungere le condizioni nominali di operazione in termini di corrente totale, energia ed uniformità del fascio. L’acceleratore di SPIDER è un triodo, con due gaps in cui è applicata tensione: dapprima la tensione di estrazione, in un gap di 6 mm, e successivamente la tensione di accelerazione in un gap di 35 mm. In un acceleratore di ioni/elettroni, la relazione tra corrente accelerata e la tensione applicata tra gli elettrodi
segue la relazione
, ovvero non è possibile aumentare la corrente di fascio se non si garantisce una sufficiente tensione; il target della prossima operazione richiede una tensione di circa 9.5kV nel primo gap, e corrispondentemente di 90 kV nel secondo gap. Nel contempo, in presenza di cariche libere nell’acceleratore, la probabilità che si formi una scarica/arco tra le superfici è incrementata di molto: in operazione, non è stato possibile raggiungere più di 8 kV di estrazione in maniera stabile, in quanto i verificavano ripetute scariche durante l’impulso, anche se in vuoto facilmente era stato possibile mantenere 12 kV in maniera continua. Inoltre, dopo la recente campagna di SPIDER, tracce di scariche e di archi sono state trovate sia sugli elettrodi (vicino al fascio di particelle) sia sulle loro strutture di supporto, a decine e decine di centimetri di distanza dalla zona attraversata dal fascio di ioni. Ambedue i gap di acceleratore mostravano queste tracce.
Infine, modifiche alle strutture di supporto degli elettrodi, e l’integrazione di una struttura metallica capace di minimizzare il campo elettrico dato dalla sorgente nella zona di deriva del fascio hanno contribuito a migliorare la funzionalità del sistema e ridurre la presenza di correnti addizionali dovute a particelle cariche. In altre parole, oltre allo studio dei dettagli dentro l’acceleratore, si valuterà anche il fenomeno dei backstreaming ions con e senza modifiche (megamesh,…).
Questo lavoro di tesi si propone di analizzare con modelli bidimensionali e tridimensionali la distribuzione del campo elettrico, ricercando possibili punti deboli su cui agire per migliorare la tenuta di tensione dell’acceleratore. Sarà necessario tenere in considerazione anche dettagli geometrici, che all’ispezione visiva hanno mostrato segni di scarica, per quantificare il campo elettrico in quelle zone e per intepretarne l’oringine. I risultati del modello dovranno essere confrontati con le tracce di scarica rilevate nella sorgente.
A seconda della disponibilità e dell’interesse dello studente, il lavoro potrebbe includere l’applicazione di tecniche ray-tracing per identificare dei punti di accumulo delle traiettorie, fenomeni di cascata che aumentano la probabilità di scarica. Secondo il piano attuale, il riassemblaggio di SPIDER dovrà concludersi entro marzo/aprile 2026, ultima finestra utile per integrare possibili migliorie prima della prossima operazione.
Tesi assegnata a: Jacopo Jinuo Lin
Proponente/Relatore RFX: A. La Rosa
Relatore accademico: E. Sartori
Capogruppo RFX: A. Rizzolo
Responsabile di Programma RFX: D. Marcuzzi
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
Questo lavoro di tesi si propone di applicare SPICE – software tradizionalmente utilizzato per la simulazione di circuiti elettrici – alla simulazione dell’operazione di un banco prova per misure di conduzione al contatto in vuoto. Sfruttando l’analogia formale tra i domini elettrico e termico (tensione come temperatura, corrente come flusso termico), lo studente svilupperà un modello a parametri concentrati non lineari, in cui le resistenze equivalenti dipendono dalla temperatura dei nodi.
Il lavoro consisterà nella modellazione in SPICE di una rete equivalente per simulare l’esecuzione di una tipica prova di conduzione al contatto in stato stazionario: lo scopo dell’attività è stimare l’impatto della dispersione di calore per irraggiamento sull’incertezza di misura al variare di parametri quali l’emissività delle superfici dei campioni e le resistenze di contatto tra diverse coppie di materiali.
Lo studente acquisirà competenze pratiche nell’uso di SPICE per modelli termici, comprenderà il comportamento non lineare delle reti termiche, e approfondirà la tematica dello scambio termico per contatto. Il progetto è adatto a studenti interessati all’analisi termica, alla modellazione numerica e alla scienza dei sistemi energetici avanzati. Il lavoro di tesi potrà includere l’esecuzione di alcune prove sperimentali per convalidare i risultati delle analisi numeriche eseguite dallo studente.
Competenze necessarie per svolgere con successo la tesi: Esami di elettrotecnica e fisica tecnica
Tesi assegnata a: Elia Casagrande
RFX Supervisor: M. Giacomin
Academic supervisor: M. Giacomin
Head of the RFX research group: M. Zuin
Leader of the RFX research program: L. Marrelli
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
Plasma turbulence plays a critical role in magnetic confinement fusion devices, regulating fusion performance and heat flux to the wall. Plasma turbulence is often investigated by means of complex and challenging three-dimensional simulations. Although significant progress has been made in characterizing turbulence in tokamaks and stellarators, only limited work has been carried out in reversed field pinch, mostly because its complex and self-organized magnetic configuration. Recently, the GBS code has been upgraded to target the simulation of reversed field pinch configurations. Building on this recent upgrade, this project will explore the feasibility of RFX-mod and RFX-mod2 GBS turbulence simulations in reversed field pinch configurations, with particular focus on the recently implemented three-dimensional Poisson’s and Ampère’s solver.
Tesi assegnata a: Tommaso Berteotti
RFX Supervisor: T. Bolzonella, P.Vincenzi, C. De Piccoli
Head of the RFX research group: D. Terranova
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
The presence of an energetic particle (EP) population strongly characterizes fusion plasmas, which will be dominated by MeV-range alpha particles in burning plasma conditions. Neutral Beam Injection (NBI), primarily used to heat plasmas to fusion temperatures, is another source of EPs that present similarities to the fusion-alpha population. NBI is currently used in most present-day devices and will also be used in the international ITER experiment1, currently being built in Cadarache (FR). This project explores non-Maxwellian distribution functions that characterize NBI energetic particles in tokamaks and their effect on the plasma, such as heating, current-drive, and torque injection. This will be done through numerical modelling, using the state-of-the-art ASCOT2 suite of codes. ASCOT is an orbit-following Monte Carlo code for simulating EPs in tokamaks by solving the Fokker-Planck equation for minority species. The complex ASCOT suite of codes has been recently rewritten3 to fit modern parallelized code standards and has an advanced post-processing Python environment. It can be used to track EP orbits and losses, to simulate the ionization and slowing down of NBI EPs, the generation and slowing down of alpha EPs, and EPs’ acceleration and slowing down due to interaction with Ion-Cyclotron waves in fusion plasmas. It can deal with full 3D machine geometry and non-axisymmetric magnetic field backgrounds. This project will apply the ASCOT code to the ITER-satellite JT-60SA tokamak4 (Naka, JP), starting the first plasma operations with NBI soon. JT-60SA case is particularly relevant for ITER due to the high injection energy of its NBI system, capable of injecting particles with energy up to 500 keV, i.e., the closest to the 1 MeV NBI system foreseen for ITER. Moreover, JT-60SA envisages the use of several injectors (in co-/counter- current or normal injection direction, with low and high injection energy, with or without a vertical tilt of the injection lines) that result in a variety of possible EP distribution functions, each of them with peculiar effects on the plasma. For instance, the modulation of NBI-induced current drive and input torque is possible, leading to unprecedented experimental conditions in the coming campaigns. Thanks to its equipment and flexibility, JT-60SA represents, therefore, the most interesting experiment to study NBI EPs in view of future ITER operations. The proposed project’s success will contribute to the modeling effort in view of the coming JT-60SA experimental campaigns and the study of ITER-relevant EP scenarios. Moreover, it will provide skills in the use of a state-of-the-art parallelized numerical code widely used for EP fusion studies, in the physics of plasma EPs and their non-Maxwellian distribution functions, and in the peculiar characteristics of the NBI-generated EP population with their beneficial effects on fusion-relevant plasmas.
Previous experience (if necessary): fusion plasma physics courses, basic programming skills (Python)
Tesi assegnata a: Tainam Mazouz
RFX Supervisor: R. Cavazzana, M. Fadone
Academic supervisor: M. Zuin
Head of the RFX research group: M. Zuin
Leader of the RFX research program: L. Marrelli
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
The behaviour of the plasmas used for Glow Discharge Conditioning (GDC) of “first wall” components, despite being widely applied in almost every fusion experiment, still lacks the full reproducibility and reliability required for the process. To study and clarify the mechanisms involved in the processes of this type of plasma and its interaction with materials and components, the FRACTAL experiment was set up at Consorzio RFX. The thesis work will primarily focus on measuring discharge characteristics under different operational conditions using Langmuir probes, followed by the analysis of the collected data to clarify the key parameters needed to identify the most stable and effective glow plasma regimes.
Previous experience: good skill in data analysis using interactive programming languages like python, Matlab or IDL are preferred.
Tesi assegnata a: Mirza Rameez
Proponente/Relatore RFX: P. Vincenzi, C. De Piccoli, T. Bolzonella
Relatore accademico: Prof. Faganello ( Aix- Marseille)
Capogruppo RFX: D. Terranova
Responsabile di Programma RFX: T. Bolzonella
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
Energetic particles (EPs) are the key ingredient of a successful nuclear fusion plasma, where fusion alpha particles will dominate plasma dynamics. In present-day devices and next-step experimental reactors, energetic particles from Neutral Beam Injection (NBI) continue to play a crucial role in heating plasmas to fusion-relevant temperatures. All EPs have in common a non-Maxwellian distribution inside the plasma, which determines physics processes such as the transfer of energy to the thermal population by Coulomb collisions, i.e. the slowing-down process. In the case of NBI, it is also possible to induce plasma current and inject torque to affect plasma rotation. These properties are strongly connected to the EP distribution function that determines the interaction with the background plasma. Ad-hoc numerical models have been developed to solve the Fokker-Planck equation that describes EP dynamics. Consorzio RFX is a leading institute in developing high-energy NBI systems, and robust numerical activity is being carried out to predict the effect of such beams on fusion plasmas.
We propose this master’s thesis to a student interested in understanding the physics of EPs in fusion plasma by performing numerical simulations with state-of-the-art codes. In particular, the student will be guided by intuitive tutorials to familiarize with the ASCOT suite of codes, a Monte-Carlo, orbit-following model widely used in the fusion community to simulate EPs in plasmas. The student will then apply ASCOT to simulate the behaviour of NBI EPs in fusion plasmas, predicting the beam-plasma interaction in international experiments such as the Divertor Tokamak Test (DTT) facility in construction in Italy or the Japanese-European tokamak JT-60SA, which will start the first NBI operations soon. The interest of these tokamaks is the high injection energy of beam particles relevant for reactor plasmas such as ITER. The student will finally discuss how different plasmas and beam characteristics will affect the interplay between EPs and background plasmas in fusion devices.
Competenze necessarie per svolgere con successo la tesi: ASCOT5 has an extensive pre- and post-processing library written in Python. We recommend a basic knowledge of the Python programming language, though knowledge of a similar language can also be sufficient since, initially, we will not require particular programming skills. Fusion plasma physics courses are recommended.
Tesi assegnata a: Tainam Mazouz
RFX Supervisor: M. Giacomin
Academic supervisor: M. Giacomin
Head of the RFX research group: M. Zuin
Leader of the RFX research program: L. Marrelli
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
Plasma turbulence plays a critical role in magnetic confinement fusion devices, regulating fusion performance and heat flux to the wall. Plasma turbulence is often investigated by means of complex and challenging three-dimensional simulations. While significant progress has been achieved in the past years
on understanding plasma turbulence in tokamaks and stellarators, turbulence in the boundary of reversed field pinch (RFP) configurations remain largely unexplored. On the other hand, RFPs provide an ideal environment to investigate the effect of magnetic chaoticity on turbulence, which is an extremely important topic in magnetic confinement fusion. A recent upgrade to the GBS code (https://gbs.epfl.ch/) has enabled the possibility to carry out the first-ever boundary turbulence simulations in RFP configurations. During the internship, which will take place at Consorzio RFX in Padua, the student will perform simulations of a reduced RFX-mod geometry with the aim of assessing the computational
feasibility of full-scale RFX-mod simulations, identifying the main numerical issues and testing possible
solutions, and providing a first insight on plasma turbulence in the reversal region of a RFP configuration.
The simulations will be performed on the largest high performance computing facilities in Europe. During the internship, the student may also collaborate with the GBS development team at EFPL, Lausanne, Switzerland.
Tesi assegnata a: Tommaso Simionato
Proponente/Relatore RFX: L. Pigatto
Relatore accademico: M. Giacomin
Capogruppo RFX: D. Terranova
Responsabile di Programma RFX: T. Bolzonella
Tipologia: Numerica, Teorica, Modellistica, Compilativa
Abstract:
Global stability of a Tokamak plasma, in the framework of ideal MHD, roughly depends on the toroidal current density and pressure gradients. The same ingredients play a crucial role in the performance (confinement, fusion production) of the same plasma, with desirable configurations often being close to stability thresholds. Assessing this proximity to unstable regimes is important during the design of operational points in future experiments.
Auxiliary heating systems, such as Neutral Beam Injectors (NBI), introduce particle populations with different energies with respect to the plasma thermal bulk. These so-called hot particles can trigger instabilities themselves as well as interact with global ideal MHD modes. When non-ideal contributions come into play, extended MHD models need to be used and validity of such models needs to be considered. In this work a drift-kinetic MHD hybrid model will be applied, through the linear stability code MARS-K, to assess the global stability of a NBI heated plasma. In this peculiar case the neutral beams provide most of the plasma pressure and are designed to achieve beam-target fusion. The thesis will start with studying the beam characteristics and evaluating the applicable physics model, implementing then simulations with increasing complexity.
Tesi assegnata a: Maria Chiara Picchini
Proponente/Relatore RFX: P. Vincenzi, C. De Piccoli
Capogruppo RFX: D. Terranova
Responsabile di Programma RFX: T. Bolzonella
Tipologia: Numerica, Teorica, Modellistica, Compilativa
Abstract:
Energetic particles will dominate the dynamics of future reactor plasmas, where fusion-alpha particle production will be the ingredient for a successful device. In present-day devices, excluding a few fusion-relevant D-T experiments, we can study the behaviour of energetic particles mainly by auxiliary, external heating systems capable of generating a suprathermal population of fast ions in plasmas. One of the primary systems that produces fast ions in plasmas is the Neutral Beam Injection (NBI) system, which is used in nearly all current experiments to heat, induce current, and provide torque to the plasma. The Divertor Tokamak Test is a tokamak under construction in Frascati (IT), aimed at contributing to ITER operations and EU DEMO design. In particular, DTT will explore heat and particle exhaust solutions, with a large amount of auxiliary power coupled to the plasma. DTT will be equipped with a high-energy neutral beam injector, which will generate energetic particles whose behaviour will be relevant for ITER and next-step devices.
Currently, numerical codes are used to predict the confinement of energetic particles in DTT, such as the state-of-the-art Monte Carlo code ASCOT, which solves the NBI ionization in the plasma and the consequent slowing down of fast ions. ASCOT can consider complex plasma backgrounds, including non-axisymmetric 3D magnetic fields, which can affect fast ion orbits and cause losses to the first wall. One typical source of 3D perturbation to the magnetic field of a tokamak arises from considering the actual position of the magnetic field coils within the tokamak, or from considering the effect of resonant magnetic perturbations used to mitigate MHD activity in the plasma.
With this master thesis project, we aim to study the physics of neutral beam-plasma interaction that leads to the generation of fast ions in the plasma, their confinement, and losses to the first wall. Thanks to the use of the ASCOT code, we will be able to track particle orbits and compute the effect of a beam fast ion population on DTT plasmas, first considering an axial-symmetric magnetic field case. We will then increase the complexity of the problem by considering the effect of 3D perturbations, quantifying the effect on fast ion losses and their position on the first wall.
Competenze necessarie per svolgere con successo la tesi: ASCOT5 features an extensive pre- and post-processing library written in Python, along with well-designed templates that facilitate code understanding. We recommend a basic knowledge of the Python programming language; however, knowledge of a similar language can also be sufficient, as we will not initially require specialized programming skills. Fusion plasma physics courses are recommended.
Tesi assegnata a: Lucia Tribbia
RFX Supervisor: M. Giacomin
Academic supervisor: M. Giacomin
Head of the RFX research group: M. Zuin
Leader of the RFX research program: T. Bolzonella
Tipologia: Numerica, Teorica, Modellistica, Compilativa
Abstract:
The scrape-off layer represents the outermost external plasma region of magnetic confinement fusion devices. This region is characterized by magnetic field lines that intercept the vessel wall, with steep density and temperature profiles. The plasma dynamics in this region plays a critical role in controlling the overall fusion performance and regulating the plasma-wall interaction. Predicting density and temperature profiles in the SOL is of pivotal importance for the design and operation of future magnetic confinement fusion devices. On the other hand, an accurate prediction of SOL profiles requires performing complex three-dimensional turbulence simulations, which are computationally very expensive. For this reason, simple transport models, which use semi-empirical or ad-doc assumptions, are often applied to determine the density and temperature SOL profiles.
The thesis project aims at providing a deep linear analysis of the main micro-instabilities at plays in the tokamak SOL in order to advance the current status of SOL turbulent transport quasi-linear models. This project is embedded in a large-scale European effort devoting to the development of accurate SOL reduced turbulence transport models. The project is divided in three main parts. In the first part, the student will familiarize with existing physical models and their linearization. The second part is dedicated to the development of a linear solver able to provide the linear properties of the most unstable modes in several turbulence regime. In the last part of the thesis project, the results of the linear analysis will be leveraged to extend existing quasi-linear models to various turbulence regimes. The thesis project will be carried out at Consorzio RFX (Padua), in collaboration with various European research institutes.Previous experience (if necessary): Good knowledge of linear and perturbation theory. Basic knowledge of plasma physics. Some familiarity with any programming language.
Tesi assegnata a: Tommaso Simionato
Proponente/Relatore RFX: M. Zuin
Relatore Accademico: M. Giacomin
Capogruppo: M. Zuin
Responsabile di Programma: L. Marrelli
Tipologia: Numerica, Teorica, Modellistica, Sperimentale
Abstract:
The thesis aims at the investigation of the excitation of Langmuir and (electron/ion) acoustic waves in a small-scale experiment where a weakly ionized plasma is produced. The aim is to replicate the condition met in the solar wind where high energy electron beams mainly from unstable flares are observed by means of satellites (such as Parker Solar Probe and Solar Orbiter) to induce high frequency phenomena with strongly nonlinear behavior.
In particular, a characterization of the relation between Langmuir waves, typically strongly damped in laboratory plasmas due to kinetic effects (Landau damping mechanism), and the ion/electron acoustic wave branches will be analyzed in condition where an intense suprathermal electron beam will be injected in a weakly-ionized plasma.
The dispersion properties of the propagating waves will be investigated in a variety of experimental conditions also in terms of background gas (He, Ar and H), pressure, and ionization fraction.
The thesis work will include an experimental activity, devoted to data acquisition and analysis, as well as a numerical activity focused on Eulerian simulations of the non-linear Vlasov-Poisson equations and of the linear Vlasov-Maxwell equations for the analysis of beam-plasma interaction, the associated generation of electrostatic waves and their propagation in linear and nonlinear regimes.
The experimental activity will be performed inside the laboratories of Consorzio RFX, Area CNR, Padova.
Competenze richieste (se necessarie): Basic plasma physics knowledge
Tesi assegnata a: Karen Spera
Proponente/Relatore RFX: M. Zuin
Relatore Accademico: M. Zuin
Capogruppo: M. Zuin
Responsabile di Programma: L. Marrelli
Tipologia: Numerica, Teorica, Modellistica, Sperimentale
Abstract:
The thesis aims at the investigation of the excitation of Langmuir waves in a small-scale cylindrical experiment where a weakly ionized plasma is produced in the presence of an inhomogeneous magnetic field. One of the aims is to replicate the condition met in the solar wind plasma where satellites (such as Parker Solar Probe and Solar Orbiter) detect electrostatic waves (typically Langmuir waves) destabilization inside the so-called magnetic holes (region of space where magnetic field intensity is significantly reduced).
Langmuir waves, which are typically strongly damped in laboratory plasmas due to kinetic effects (Landau damping mechanism), will be induced through the excitation of the two-stream instability by using a suprathermal electron beam propagating in a background plasma. The role of an externally applied spatially inhomogeneous magnetic nozzle, in determining the dispersion properties of the waves, both in the direction parallel and perpendicular with respect to the magnetic field itself, will be investigated in a variety of experimental conditions also in terms of background gas (He, Ar and H), pressure, and ionization fraction.
The thesis work will include an experimental activity, devoted to the preparation of the device and of the diagnostic system, to data acquisition and analysis, as well as a numerical activity focused on Eulerian simulations of the non-linear Vlasov-Poisson and the linear Vlasov-Maxwell equations for the analysis of beam-plasma interaction and the associated generation of electrostatic fluctuations.
The experimental activity will be performed inside the laboratories of Consorzio RFX, Area CNR, Padova.
Competenze richieste (se necessarie): Basic plasma physics knowledge
Tesi assegnata a: Irene Malfatti
RFX Supervisor: A. Stagni
Academic supervisor: F. Califano (UNIPI)
Head of the RFX research group: M. Zuin
Leader of the RFX research program: T. Bolzonella
Tipologia: Sperimentale, Teorica, Modellistica, Compilativa
Abstract:
Predicting, extrapolating and optimizing the heat and particle fluxes on material surfaces, so as to avoid damaging the first wall components, still represents a key challenge in view of safe and reliable operation of future large tokamak devices. In particular, the power and particle exhausts travelling radially towards the plasma-facing components are largely determined by the transport processes taking place in the scrape-off layer (SOL) region at the tokamak boundary. Given their inherently non-linear and turbulent nature, a common understanding of the physical mechanisms responsible for SOL radial transport has not been reached yet. Recent observations have highlighted the importance of the plasma conditions near the separatrix or last closed flux surface (LCFS), separating the confined region from the open field lines comprising the SOL. Leveraging these results, the separatrix operational space (SepOS) modelling framework has been developed for a description of SOL transport processes based on a reduced set of parameters. So far, this framework has been successfully exploited to predict the edge operational boundaries (e.g. L-H transition, density limit, etc.) on ASDEX-Upgrade, while work for its extension to other machines is underway. This thesis project is devoted to making progress in extending the SepOS framework to plasma discharges in the TCV tokamak (Lausanne, Switzerland), which is particularly suited for this task thanks to its great flexibility in the possible plasma configurations and scenarios. This work is structured as follows: the first part is devoted to getting familiar with the signals and working principles of the main SOL profile and fluctuation diagnostics, as well as analyzing their data within a wide range of TCV working scenarios. The outcome of this data analysis phase will be exploited to systematically estimate the relevant edge operational quantities and build a TCV-specific SepOS parameter space, discriminating several operational and disruptive boundaries. Finally, the results will be exploited to predict the operational point and qualitatively assess the SOL transport characteristics of next experimental and reactor-level devices, like DTT and ITER.
Previous experience (if necessary): Basic knowledge of Plasma Physics and fluid models. Knowledge of data analysis techniques and Python is welcome, but not necessary.
Tesi assegnata a: Giovanni Mancuso
RFX Supervisor: U. Giuliani
Academic supervisor: G. Zollino
Head of the RFX research group: A. Maistrello
Leader of the RFX research program: S. Peruzzo
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
The thesis work will focus on the development and use of the model COMESE to produce energy scenarios for the analyses of a decarbonized power system. The renewable potential for solar and wind power generators in the Italian territory will be taken into account in order to define the better exploitable mix of these sources, with a high detail with respect to different generators models for both energy sources. This approach aims at assessing which is the best trade-off between the efficiency of the single generators and their land-occupation, with a total system-costs perspective.
Previous experience: MATLAB basic skills
Tesi assegnata a: Martina Canali
RFX Supervisor: D. Bonfiglio, L. Spinicci
Academic supervisor: M. Passoni – Polimi.
Head of the RFX research group: S. Cappello
Leader of the RFX research program: L. Marrelli
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
This project aims at a substantial enlargement of the predictive capabilities of the three-dimensional magneto-hydrodynamic (3D MHD) nonlinear code SpeCyl. In continuation of recent PhD work, which led to the modelling of a thin resistive wall at the plasma interface, with self-consistent flow and magnetic field conditions, the candidate will be asked to contribute to the progressive improvement of SpeCyl’s boundary conditions through the implementation of a second passive shell at a finite distance from the plasma. Together with the future further development of control coils, this project is part of a process of increasing realism in the nonlinear modelling of the RFX-mod experiment, which is also useful to effectively anticipate the dynamics in the forthcoming configuration, RFX-mod2.
The candidate will therefore be required to carry out analytical/numerical work to determine and implement the new double-wall boundary conditions, in full consistency with the MHD model already present in the code. The correctness of the implementation will then be verified through a benchmark of the new double-wall module against analytical models of the MHD linear stability theory.
Further numerical development work could be evaluated, if the project timing will allow for it. The final version of the code, produced by the candidate, will be used in predictive modelling studies of MHD dynamics, investigating important plasma instabilities such as quasi-laminar states of the reversed-field pinch configuration.
Previous experience (if necessary): n.a.
Assegnata a: Francesco Galeazzi
RFX Supervisor: M. Veranda, F. Sattin
Academic supervisor: V. Russo (Polimi)
Head of the RFX research group: S. Cappello
Leader of the RFX research program: L. Marrelli
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
The project involves an implementation of the ion heating model by low-frequency waves, as described in the paper [F. Sattin, D.F. Escande, Physical Review E, vol. 107, art. 065201 (2023)]. The candidate is asked to specialize the model to the geometry of a Reverse Field Pinch device during magnetic reconnections. Numerical quantities involved (amplitude and frequency spectrum of excited Alfvén waves, scale length of the reconnecting layer, …) will be extracted from a database of numerical simulations performed with the visco-resistive nonlinear MHD code SPECYL. The final output is a rate of ion heating, to be compared with expected levels. In particular, numerical plasma configurations will be tailored to published MST data regarding different ion heating in order to reproduce experimental findings/measurements
Tesi assegnata a: Lorenzo Martinelli
Proponente/Relatore RFX: G. Palumbo
Relatore accademico: D. Della Sega
Capogruppo RFX: M. Valente
Responsabile di Programma RFX: L. Marrelli
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
The recently developed Fusion-Fission Hybrid Reactor (FFHR) proposal represents an innovative approach to nuclear fusion, integrating a Reversed Field Pinch (RFP) reactor with sub-critical fission modules. This concept, aimed mainly at tritium breeding, requires a more deepen study of reactor materials due to the implementation of superconducting magnetizing and equilibrium coils. A key challenge is mitigating the high-energy neutron flux from the plasma to prevent performance degradation of superconducting components, while ensuring steady efficient operation of the in-core components.
This study focuses on the selection and optimization of blanket and core materials, beginning with an investigation of the elements reported in the literature for neutron attenuation, taking into account their characteristics and performance.
A numerical model based on a Monte Carlo approach will be developed to assess neutron shielding requirements while balancing thermal and electromagnetic constraints. Through an iterative process of material proposal, simulation, and validation, the research must ensure compliance with shielding, structural and operational limitations.
The outcomes will contribute to enhancing the feasibility of FFHR systems by optimizing neutron shielding strategies for superconducting fusion devices.
Competenze necessarie per svolgere con successo la tesi: Basic understanding of the Reversed Field Pinch (RFP) machine design and its key components. Experience in numerical modeling using Monte Carlo methods and statistical analysis. Proficiency in MATLAB programming language, with a focus on simulation and data processing techniques
Tesi assegnata a: Antonio Rigato (POLIMI)
Relatore RFX: D. Abate, L. Marrelli
Relatore Accademico: N. Marconato
Tipologia: Modelling, Teorica, Numerica, Compilativa
Abstract:
The present thesis focuses on the electromagnetic modelling and design of a multi gap solution for the passive stabilizing shell of magnetic confinement fusion experiments in reversed field pinch (RFP) configurations. The modelling activity aims at studying the effects of multiple gaps in the passive stabilizing shell surrounding a RFP plasma, by means of electromagnetic models with different level of complexity. The effect of different number and shape of gaps will be investigated in terms of plasma stability and engineering complexity, by developing dedicated numerical codes based on FEM/BEM approach. The selected multi gap solution will then be analysed in terms of engineering design and manufacturing processes.
Competenze richieste: Elettrotecnica, Elettrotecnica computazionale, conoscenza base di linguaggi di programmazione e ambienti di sviluppo (es.: COMSOL, ANSYS, MATLAB)
Tesi assegnata a: Christian Garlani
Proponente/Relatore RFX: B. Pouradier-Duteil/ M. Fadone
Relatore Accademico: E. Sartori
Capogruppo: A. Rizzolo
Responsabile di Programma: D. Marcuzzi
Abstract:
Gli iniettori di neutri sono riscaldamenti ausiliari fondamentali per le macchine da fusione nucleare: la formazione del fascio di ioni negativi, precursore del fascio di neutri, avviene estraendo ioni negativi da un plasma di idrogeno. Poiché in una scarica di idrogeno la densità di ioni negativi è molto bassa, va massimizzata grazie alla evaporazione di cesio, che ricoprendo le superfici metalliche affacciate al plasma, ne riduce la funzione lavoro; pertanto, atomi di idrogeno che impattano sulla superficie possono estrarre un elettrone dalla superficie e venire riemessi come ioni negativi. Dato il ruolo fondamentale del cesio nella produzione di ioni negativi, l’uniformità del fascio risultante dipende dalla uniformità della copertura di cesio, specialmente alle superfici vicine ai fori da cui il fascio viene estratto. Inoltre, lo stato di adsorbimento locale e la sua funzionalità, quantificabile nella stessa funzione lavoro, tanto quanto le energie di desorbimento e la probabiltià di “sticking” possono dipendere dai gsa residui e sono estremamente importanti nella dinamica.
L’esperimento “CATS” è equipaggiato con varie diagnostiche dedicate alla caratterizzazione della quantità di cesio evaporato (Langmuir-Taylor detector al forno) della distribuzione angolare della emissione dal forno e la densità in camera (Langmuir-Taylor detector mobile e Laser Absorption Spectroscopy); per la prima volta si potrà misurare simultaneamente la probabilità di deposizione (microbilancia al quarzo), la funzione lavoro delle superfici esposte al vapore di cesio (metodo di Fowler per misurare lo yield fotoelettrico), e verificare le energie di desorbimento (Temperature Programmed Desorption), e può utilizzare una iniezione controllata di gas (aria, argon, idrogeno) per testare il ruolo di questi gas in questi parametri.
I parametri di stricking, le energie di desorbimento, lo stato di copertura (monolayer/multilayer) e il corrispondente valore della funzione lavoro dedotti dall’esperimento si potranno impiegare nei modelli di trasporto del cesio in SPIDER.
Lo studio proposto consiste in 1) la partecipazione alla campagna sperimentale di misure, e nella analisi dati. 2) nella implementazione dei coefficienti dedotti dall’esperimento nel codice di trasporto e lo studio dei recenti risultati di SPIDER. Inoltre, a seconda del successo della prima fase e del tempo a disposizione e della predisposizione dello studente, 3) si verificheranno le implicazioni nella procedura di cesiatura della modifica dell’ugello di emissione del cesio dal forno.
Tesi assegnata a: Martino Bizzotto
Proponente/Relatore RFX: L. Pigatto
Relatore accademico: P. Bettini
Capogruppo RFX: M. Brombin
Responsabile di Programma RFX: T. Bolzonella / L. Marrelli
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
Controlling plasma evolution in a fusion experiment, being able to do so in real-time, is one of the keys for success of a new generation of devices and ITER most of all. External 3D magnetic perturbations represent a multi-purpose control tool that can be applied to different plasma instabilities. In this work we address the correction of Error Fields in tokamak experiments. Error Fields are spurious non-axisymmetric components of the equilibrium magnetic field that can couple to the plasma and trigger instabilities, often leading to a violent termination of the plasma itself. The problem of preventing, estimating and correcting EFs is of growing in importance together with the engineering and manufacturing complexity of magnets in nowadays experiments. This thesis work aims at developing a simulation tool, based on Matlab Simulink, to calculate Error Field correction currents in dedicated 3D coils. The first application will the ASDES-Upgrade (AUG) Tokamak, in support of experiments. The known EF pattern of AUG will be implemented, along with the correction coil geometry (B-coils) and the plasma response model separately calculated. This simulation tool will be used to calculate EF correction currents in planned experiments. The candidate will develop optimization of these currents based on the available number of actuators and implement time dependencies from EF sources and plasma state changes. Depending on the available time, an application for the RFX-mod2 experiment can be foreseen. In this case a more complex optimization of the currents will be needed, given the larger number of 3D coils.
Competenze necessarie per svolgere con successo la tesi: Conoscenza di base ambiente Matlab (con Simulink), Python consigliato ma non necessario
Tesi assegnata a: Ilaria Lugato
Proponente/Relatore RFX: A. Rigoni Garola
Relatore Accademico: A. Rigoni Garola
Capogruppo/Servizio: R. DeLogu
Responsabile di Programma: D. Marcuzzi
Tipologia: Sperimentale, Teorica, Numerica, Compilativa
Abstract:
To deliver power to the fusion plasma in the ITER experiment, two neutral beam injectors (NBIs) have been designed. Each injector will provide 17 MW of heating power through 23-meter-long beamlines directed toward a four-meter-diameter plasma vessel. To deposit sufficient power in the plasma core, rather than at the edges, the injected neutral particles must reach energies of approximately 1 MeV. Achieving such high energies significantly increases the complexity of the neutral beam system, making it one of the most advanced auxiliary heating systems ever developed for a fusion reactor.
The SPIDER experiment, located in Padua at the Neutral Beam Test Facility (NBTF), represents the first step toward optimizing this technology. Its main objectives are to improve ion source performance, optimize the use of cesium vapor, and verify the uniformity and stability of the extracted ion beam during long-duration pulses.
Currently, the diagnostic and control system of SPIDER relies on a well-established data acquisition and storage framework known as MDSplus. This system efficiently handles both fast transient data acquisition and long-pulse data streaming. However, despite its robustness and proven performance, MDSplus’s fixed communication protocol, which is typically one of its key strengths, can become a limiting factor when multiple heterogeneous clients concurrently request data access. This issue is particularly evident when several users attempt to retrieve live signal updates from the server during an ongoing experimental session, while data are still in the online state and has not yet been transferred to offline storage.
To overcome this limitation, the proposed work aims at the design and implementation of a flexible communication protocol layer that enhances MDSplus’s data distribution capabilities. This new component will act as an interface within the data acquisition chain, reading relevant diagnostic quantities and exposing them through a more adaptable and efficient distribution mechanism. Two candidate technologies for implementing this layer are FlatBuffers (maintained by Google) and Cap’n Proto (maintained by Cloudflare), both recognized for their high-performance data serialization and efficient protocol definition.
The thesis will propose a software implementation based on one of these schema languages, functioning as a middleware between the MDSplus system and a broker component (such as Redpanda or NNG). This middleware will enable a publish/subscribe mechanism for real-time data distribution among multiple clients. The effectiveness of the proposed solution will be evaluated through quantitative performance metrics, comparing its results against the standard event-streaming architecture currently used in MDSplus, to assess the degree of performance improvement and scalability achieved.
Competenze richieste (se necessarie): Sistemi real-time e conoscenza dei linguaggi C++ e Javascript. Apprezzata conoscenza pregressa di sistemi per la definizione di protocolli e RPC (protocol buffers, gRPC) e sistemi di comunicazione distribuita (come Kafka, Pulsar).
Tesi assegnata a: Manuel Rigobello
RFX Supervisor: C. Bustreo
Academic supervisor: G. Zollino
Head of the RFX research group: A. Maistrello
Leader of the RFX research program: S. Peruzzo
Tipologia: Numerica, Teorica, Modellistica, Compilativa
Abstract:
The thesis will focus on the development and application of the COMESE model to generate energy scenarios for analyzing a decarbonized power system. Currently, the model includes a simplified simulation module that operates over a limited time span rather than the full calendar year. By enhancing this feature, the thesis will investigate the errors introduced when using representative time periods (such as days, weeks, or months) instead of simulating the entire year. The objective is to evaluate the trade-off between computational efficiency and the loss of accuracy resulting from reduced temporal resolution in power system optimization and feasibility studies
Previous experience (if necessary): MATLAB basic skills
Tesi assegnata a: Tommaso Donega
RFX Supervisor: U. Giuliani
Academic supervisor: G. Zollino
Head of the RFX research group: A. Maistrello
Leader of the RFX research program: T. Bolzonella
Tipologia: Numerica, Teorica, Modellistica, Compilativa
Abstract:
The student will upgrade the COMESE model and develop a routine to run an optimization process based on multiple objectives. The current optimization routine is based on a single objective function (the LCOTE, an average levelized sytem cost). Other objective functions such as land occupation, carbon emissions, RRE (Rare Earth Elements) and strategic materials consumptions will be considered as an addition in a multi-ojective optimization process. Also the approach known as “modelling to generate alternatives” will be explored, in order to explore the features of the near-optimal region of the domain in an energy scenario.
Previous experience (if necessary): MATLAB basic skills
Tesi assegnata a: Giulio Zoppolato
RFX Supervisor: R. Cavazzana
Academic supervisor: N. Marconato
Head of the RFX research group: M. Brombin
Leader of the RFX research program: L. Marrelli
Tipologia: Numerica, Teorica, Experimental, Compilativa
Abstract:
Magnetic measurements are a fundamental element for the operation of current experimental devices and future commercial fusion reactors. High-performance plasma control requires signal precision and noise immunity. This thesis project focuses on the dimensioning, design, and laboratory characterization of specialized line termination adapters. These components are extremely critical for ensuring signal integrity throughout the entire measurement chain—comprising magnetic sensors (probes), long-distance transmission lines, and front-end acquisition electronics.
The activity will involve in modeling and simulating the transmission line behavior, design the matching network, with experimental validation through laboratory testing of the full measurement chain.
Previous experience: Knowledge of circuit simulator (PSpice or LTSpice).
Basic skills in signal processing and data analysis (Matlab or Python).
Tesi assegnata a: Gianluca Gallio
RFX Supervisor: M. Giacomin
Academic supervisor: M. Giacomin
Head of the RFX research group: M. Zuin
Leader of the RFX research program: L. Marrelli
Tipologia: Data Analisys, Teorica, Modellistica, Compilativa
Abstract:
Turbulence in the boundary plasma region of magnetic confinement fusion devices plays a critical role on the overall fusion performance and on the heat exhaust. Understanding turbulence dynamics in this region is particularly challenging due to the wide spatial and time scale ranges that are involved as well as the complex magnetic geometry. For this reason, state-of-the-art three-dimensional turbulence simulations are often necessary to disentangle the plasma dynamics in this region. In the past twenty years, advanced two-fluid flux-driven global turbulence codes have been developed and applied to investigate tokamak boundary turbulence. These simulations rely on a collisional closure, which requires a sufficiently large plasma collisionality, defined as the ratio of the parallel connection length to the electron mean free path. However, this condition may be violated in the next-generation magnetic confinement fusion devices, where the electron temperature at the plasma edge is expected to be significantly larger than that in present-day tokamak experiments. Consequently, gyrokinetic codes targeting the plasma boundary have been developed in recent years.
The thesis project consists in developing a synthetic diagnostic that mimics the U-probe diagnostic of RFX-mod. This synthetic diagnostic will be applied to the simulation data obtained from two different codes, which implement two different models. The first code (GBS) implements a two-fluid Braginskii model, while the second code (GENE-X) implements a gyrokinetic model. Simulation data of a RFX-mod discharge are already available for the analysis. The thesis project is structured along three main objectives. First, the student will develop the synthetic U-probe diagnostic in Python. Second, the results of the synthetic diagnostic, applied to the simulation outputs from the two codes, will be compared. Third, the synthetic diagnostic data will be directly compared to experimental measurements from the U-probe.
Tesi assegnata a: Alessandra Alberton