Interaction of rapid magnetic fields with plasmas and implications to pulsed-power systems

The behavior of rapidly rising magnetic fields decisively affects the operation of plasma opening switches, high-power transmission lines, and particle-beam diodes. Here, we describe recently observed novel phenomena in the interaction of magnetic fields with plasmas in such systems. The understanding of the underlying physics is used to design and optimize plasma opening switches and their coupling to loads. High-resolution spectroscopic methods, with the aid of plasma doping techniques, were used to obtain the time-dependent 2-D distributions of the magnetic field, ion velocities, electron density, and electron energy distribution. The results showed simultaneous rapid magnetic field penetration and plasma reflection accompanied by ion-species separation [A. Weingarten et. al., Phys. Rev. Lett. 87, 115004 (2001)]. These phenomena strongly modify the plasma dynamics, thereby influencing the effective switch impedance and the resultant coupling of the power to the load. The current conduction and switch operation are also found to be highly influenced by the electron density distribution and plasma composition. Possible ways to improve the system operation, brought about by these findings, are suggested.