Optical emission spectroscopy investigation of the current sheet in a small-bore parallel-plate electromagnetic plasma accelerator

The optical emission spectrum of the propagating current sheet in a small-bore parallel-plate electromagnetic plasma accelerator has been studied. The accelerator is powered by a fourteen stage pulse forming network, which yields a damped oscillation square wave of current with a pulse width of 20.5 μs. The movement of the first current sheet and the second current sheet is identified using three single magnetic probes placed at various axial positions. Current sheet canting is measured by two double magnetic probes. The spectrum of the current sheet is measured using a spectroscopic system. The electron density of the current sheet plasma is determined via Stark broadening of the hydrogen Hα line. The current sheet is almost perpendicular to the electrode. The current sheet electron density increases as the current sheet propagates. The current sheet electron density is mainly determined by the prefill pressure rather than the discharge current. The impurity charged particles caused by ablation of the ba...