Relaxation electric fields in spheromaks

Abstract

The authors apply the results of the edge helicity dissipation model (see T.R. Jarboe and B. Alper, 1987) to determine the relative magnitudes of electric fields during relaxation in spheromaks. This is achieved by quantifying the average electric field in the plasma edge region generated by flux decay and relaxation mechanism(s). It is shown that relaxation electric fields can be as much as three times the flux decay field in the edge. The model also correctly predicts no relaxation electric field when the spheromak is a cold, purely resistively decaying object. In addition, the model provides an estimate for the quantity of magnetic decay power from relaxation, which can be as much as 75% of the total decay power.<>