Positive consequences of dynamo: RFP self-organization and sustainement
In RFX, we can routinely produce the magnetic configuration with a variety of setting up processes. In particular, by carefully adjusting the breakdown phase, we can start the discharge at very low toroidal field letting the dynamo generate pratically all the toroidal flux in the discharge, as shown in the middle panel of the figure. In addition the discharge can be maintained in the RFP configuration for time intervals much longer than the resistive diffusion time and as long as the applied toroidal electric field is sustained. This shows that the dynamo mechanism driving the poloidal current in the plasma is robust and reliable.
The plasma current (continuous line),
average toroidal field (dashed line) and edge toroidal field (dotted line) are shown for three RFX pulses.
In the middle panel, it can be noticed that the average toroidal field in the plasma is well above the toroidal field at the onset of the discharge.