Neutralization of Kiloampere Beams of Relativistic Electrons with Different Durations in a Plasma Column with a Leading Magnetic Field

In experiments on plasma heating during the passage of a relativistic electron beam with a current ~10 kA through a plasma column, the electric and magnetic fields of the beam have to be compensated by the current induced in the plasma, i.e., the so-called charge and current neutralizations of the beam have to occur. In the earliest experiments on injection of high-current relativistic electron beams into a plasma with a magnetic field, the effects of plasma neutralization of the electron beam’s internal electromagnetic field were observed. At the same time, the dynamics of these neutralization processes also depends on the ratio between the duration of the leading edge of the beam current and the flight time of its electrons along the plasma column length. This work describes the results of two substantially different series of experiments on the neutralization of an electron beam with a current of about 10 kA in a plasma column under a strong (4 T) leading magnetic field. In the first series of experiments, the leading edge of the beam current was ≈5 ns and its duration was about 50 ns. In the second series of experiments, the leading edge of the current beam was ~0.1 μs and its duration was ≈5 μs.