Observations of the Spatial Evolution of a Potential Hump into a Strong Double Layer in a High-Voltage Straight Plasma Discharge

The propagation and spatial evolution of a potential hump generated explosively near the cathode were observed in the current-limiting phase of a high-voltage straight discharge with a preexisting hydrogen plasma. Potential profiles along the axis numerically calculated from the real-time E field data demonstrate the evolution of a potential hump into a strong double layer (asymmetric electron hole) with an inverse potential jump (eφDkTₑ10³) as moving toward the center of the device with a mean velocity (1.2-1.8) ×{} 10⁸ cm/sec.