High-power ion beam production in focusing diode systems

Results of experimental investigations into the generation of high-power ion beams in coaxial magneto-isolated diodes (MID) with internal cathode of the ''squiral wheel'' type are presented. Cathodes with the diameter of 79 mm and 130 mm are used. Anode-cathode (A-C) gap is changed from 7 to 20 mm, anode lenth is 50-170 mm. MID with azimuthally isolating magnetic field and axially isolating magnetic field are investigated. It is shown that instability of the drift magnetized flux in diode with an azimuthal field brings about the change of energy of drifting electrons and their return to cathode with higher energies which causes the appearance of electron current directed inside cathode, as well as by fast neutralization, of A-C gap within 50-60 ns. Ion beam density at diode axis is 2.1 kA/cm2. Conclusions are made that MID with open electron drift is perspective for accelerators operating in the nanosecond range