Review of electrostatic plugging

Abstract

Using electric fields to diminish end losses from open magnetic plasma confinement systems is equivalent to magnetically shielding the grid wires of an electrostatic plasma confinement device. Electrostatically plugged magnetic cusps confine electrons magnetically in the perpendicular direction and electrostatically in the parallel direction, and ions are purely electrostatically confined in both directions. Theoretical estimates have been made of confinement times, electron density, plasma potential, and plasma temperatures. Experimentally, plasmas with n = 5 x 10/sup 12/ cm/sup -3/, T/sub i/ = 1 keV, tau = 5 msec, have been confined by cusp fields of about 10 kG with applied voltages approximately 10 kV. Fusion reactors with (fusion power)/(injection power) identical with Q approximately 5 appear feasible using B approximately 80 kG, applied voltage approximately 300 kV, if extrapolations from present experiments hold. Electrostatically plugged cusps are similar in some ways to Tandem Mirrors, to Tormac, and to SURMAC plasma confinement systems.