Plasma vertical stability and feedback control for CIT

The plasma vertical stability and vertical position feedback control are examined for the Compact Ignition Tokamak (CIT). The Tokamak Simulation Code (TSC) is used to determine the plasma growth times in the absence of control, and to simulate feedback control with realistic features to determine the requirements on the internal control coils and their power supplies. Numerical simulations have been carried out using TSC to assess the vertical stability and feedback control of the vertical position in the CIT. The stability calculations indicate this particular design has a vertical growth time of 16.5 ms, which is long enough to allow time-delays in the control and not require unreasonable power supply response times. Vertical position control can be achieved with either of two internal controllers presented. The maximum vertical offset from the midplane that is expected to be controlled is 2 cm. With the most recent power-supply design, this can be achieved with a maximum current of 400 kA, a maximum voltage of 500 V, and a maximum time delay of under 4 ms.