Ion betatron

Summary form only given, as follows. An approach for increasing the space charge limit of a betatron is described. The space charge of the ion beam is completely neutralized by electrons or a background plasma. The ions to be accelerated have a large gyroradius and are nonadiabatic compared to the background electrons or ions, which are adiabatic. Applying a toroidal electric field by changing the flux through the large ion orbit accelerates only nonadiabatic ions. The adiabatic particles can only drift and are therefore magnetically insulated. Ions can be trapped by injecting a neutralized ion beam that is produced in a magnetically insulated ion diode pulsed at a few hundred kiloelectronvolts. The collective trapping process is quite simple.<>