ITER Negative-Ion Beam Source — Extraction Simulator

Physics Model

the extracted current density is limited by two independent mechanisms: the Child-Langmuir-Blodgett (CLB) law — J_CLB = 0.000470 · V^3/2 [A/m²] — which sets the maximum current the extraction gap (between plasma grid PG and extraction grid EG) can transport at a given voltage; and the RF plasma production limit — J_RF = 0.49 · P_RF [A/m²] — which caps the available ion density. The actual extracted current density is therefore J_ext = min(J_CLB, J_RF), and the beam perveance at the extraction is Π_ext = J_ext / V^3/2.