Magnetic insulation of extraction Applied-B ion diodes

Abstract

The difference in the operation of extraction geometry versus radial geometry Applied‐B ion diodes is explained through the use of a general magnetic insulation condition for cylindrically symmetric ion diodes which is expressed in terms of the magnetic stream function. We find that Applied‐B extraction geometries attempted so far have suffered from a magnetic field configuration defect which explains their rather poor performance. We present solutions to the extraction Applied‐B ion diode problem, as well as 2D, electromagnetic particle‐in‐cell simulations of an example solution.