Study of generalized toroidal cusp configurations

Hot electrons as well as hot ions are a desirable feature of any fusion device. We investigate by particle simulations (in slab geometry) and simple theory two variants of the Toroidal Cusp Experiment (TCX) with an eye to achieving hot electrons, while retaining its large direct ion heating feature. A toroidal field added to the TCX configuration, with cusp magnets arranged poloidally to partly cancel cusp trapping of the electrons insures electron flow across the cusps and electron heating. Helical winding of the cusp magnets around the torus with pitch theta greater than or equal to (m/M)/sup 1/2/ allows trapped electron flow on average helical paths; however, ions can still flow across the cusps and the J . E heating of ions and electrons can be varied at will