Ion Confinement by Rotation in Magnetic Mirror Geometry

Abstract

When a generally radial electric field is imposed upon a mirror magnetic field configuration, the resulting system has an increased ability to contain plasma between the mirror regions. The motion of the ions consists of a drift around the axis of symmetry upon which is superimposed a spiralling motion. The guiding center motion departs from the direction of magnetic flux surfaces. An adiabatic invariant is derived for the drift component of the motion, and an expression is derived for the mirror enhancement brought about by the E×B drift. The departure of the guiding center of a particle from a flux surface and the energy balance of its secular motion are calculated by using the adiabatic invariant.