Formation of narrow low-energy high-intensity electron beams

The process of formation of high-density low-energy (5–10 keV) pulsed electron beams of small diameter (on the order of a few millimeters) in a gun of the “channel-spark” type is studied. It is shown that beams with a rate of rise of the current exceeding 10$^{11}$ A/s and an amplitude exceeding the Alfvén current by a factor of 1.5–2.0 can be obtained in experiments with intense preionisation of the transport channel combined with a pulsed supply of the accelerating voltage to the cathode. In the optimal pressure mode, the current density at a distance of 2–3 cm from the gun outlet is 40–25 kA/cm$^2$, which will ensure ablation of most solid targets.