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A transient pulsed arc was studied with narrow band 696.5 nm filters. The arc energy distribution was considered by a ratio: a certain region energy (intensity × region area)/sum. The results indicated a large intensity region appeared with a pulsed arc, which were considered as high-energy regions. They increased while the low-energy regions were compressed. The distribution ratio was changed by the 'waves rush' pattern with a large current or pulsed arc. Spurious energy concentration was found at the bottom of the arc. The pulsed arc with 10 kHz at 100 A had optimal characteristics in geometry and energy distribution. The essence of the pulsed arc was considered as constricting energy regions and creating high-energy density. 'Onion-Kasuga' algorithm was proposed to reconstruct the arc intensity.

A 1D1V hybrid Vlasov-fluid model was developed for this study to elucidate ionization oscillations of Hall thrusters (HTs). The Vlasov equation for ions velocity distribution function (IVDF) with ionization source term is solved using a constrained interpolation profile conservative semi-Lagrangian (CIP-CSL) method. The fourth-order weighted essentially non-oscillatory (4th WENO) limiter is applied to the first derivative term to minimize numerical oscillation in the discharge oscillation analyses. The fourth-order spatial accuracy is verified through a 1D scalar test case. Nonoscillatory and high-resolution features of the Vlasov model are confirmed by simulating the test cases of the Vlasov–Poisson (VP) system and by comparing the results with a particle-in-cell (PIC) method. A 1D1V Hall thruster simulation is performed through the hybrid Vlasov-fluid model. The ionization oscillation is analysed. The macroscopic plasma properties are compared with those obtained from a hybrid PIC method. The comparison indicates that the hybrid Vlasov-fluid model yields noiseless results and that the steady-state waveform is calculable in a short time period.