Energy Efficiency Analysis of the Discharge Circuit of Caltech Spheromak Experiment
The Caltech spheromak experiment uses a size A ignitron in switching a 59-μF capacitor bank (charged up to 8 kV) across an inductive plasma load. Typical power levels in the discharge circuit are ~200 MW for a duration of ~10 μs. This paper describes the setup of the circuit and the measurements of various impedances in the circuit. The combined impedance of the size A ignitron and the cables was found to be significantly larger than the plasma impedance. This causes the circuit to behave like a current source with low energy transfer efficiency. This behavior is expected to be common with other pulsed plasma experiments of similar size that employ an ignitron switch.
© 2009 IEEE. Manuscript received June 9, 2009; revised September 25, 2009. First published November 20, 2009; current version published January 7, 2010. The authors would like to thank F. Cosso, M. Brown, S. Hsu, D. Felt, and S. You for building and maintaining the Caltech spheromak discharge circuit.
Published - Kumar2010p6995Ieee_T_Plasma_Sci.pdf