Anomalous acceleration of ions in a plasma accelerator with an anodic layer

Abstract

In a plasma accelerator with an anodic layer (PAAL), we discovered experimentally the effect of 'super-acceleration' of the bulk of the ions to energies W exceeding the energy equivalent to the discharge voltage V d. The E×B discharge was ignited in an environment of atomic argon and helium and molecular nitrogen. Singly charged argon ions were accelerated most effectively in the case of the largest discharge currents and pressure P of the working gas. Helium ions with W>eV d (e being the electron charge) were only recorded at maximum pressures. Molecular nitrogen was not accelerated to energies W>eV d. Anomalous acceleration is realized in the range of radial magnetic fields on the anode 2.8×10-2 B rA 4×10-2 T. It was also found analytically that the cathode of the accelerator can receive anomalously accelerated ions. In this case, the value of the potential in the anodic layer becomes higher than the anode potential, and the anode current exceeds some critical value. Numerical modeling in terms of the developed theory showed qualitative agreement between modeling data and measurements.

Ion activity in quasi-neutral current sheets and discharge plasma in crossed electric and magnetic fields

“…The scheme of the two-chamber TAL used in this experiment is shown in Figure 3 [ Bardakov et al, 2016Bardakov et al, , 2018. Ion energy distribution functions were measured by a three-grid RFA at the TAL outlet.…”