Arc Plasma Propagation and Arc Current Profiles

Abstract

When electrical arcs occur in space, a plasma expands away from the arc-site, neutralizing adjacent surfaces (a current), and causing a current to be produced at the arc-site (source of neutralization current). The speed of this plasma expansion depends on the plasma species, which in turn depend on the ionizable materials near the initial electrostatic discharge (ESD) site. Based on laboratory experiments undertaken as part of the U.S. round-robin experiments on plasma propagation speed, a scenario for arc plasma propagation and arc current profiles is presented. It is found that the complex arc current profiles invariably seen in laboratory arcs are due to a multicomponent plasma, where each plasma species expands away from the arc-site supersonically and with approximately constant velocity. Apparent slowing of the arc plasma seen in high-speed video cameras is caused by the density depletion of the lightest (most rapid) plasma component first and heavier (slower) plasma components later. Electron currents onto surfaces originate at the arc-site, and the conductive arc plasma is a conduit for these currents. Sudden, simultaneous onset of arc currents at all distances from the arc-site is the result of blowoff currents, making all surfaces more positive, which then attract ambient electrons. Sudden, simultaneous cutoff of arc currents at all distances from the arc-site is the result of collapse of the plasma due to conditions at the arc-site. The ionization at the arc-site during the arc is seen to be rapidly variable, with variations on the nanosecond timescale. This model not only makes the varied plasma velocities reported in the literature understandable, but it also makes predictions about the arc radiofrequency interference (RFI), contamination produced by the arcs, and the total charge in an arc possible. Arc-site materials are suggested which, being hard to ionize and with massive ions, minimize arc currents and maximize arc current rise times.

Spectral Characteristics of GEO Satellite Arcing – 300 To 350 MHz

“…Theoretically, the arc current duration of vacuum flashover arcs should depend on the extent of the surface to be discharged and the speed of the ions in the expanding plasma cloud [3]. In Ferguson et al [2,4], arc durations of up to 144 microseconds are considered, and in Ferguson et al [3], it is shown that arc durations ("spike widths") of up to 134 microseconds are probably real.…”

“…Theoretically, the arc current duration of vacuum flashover arcs should depend on the extent of the surface to be discharged and the speed of the ions in the expanding plasma cloud [3]. In Ferguson et al [2,4], arc durations of up to 144 microseconds are considered, and in Ferguson et al [3], it is shown that arc durations ("spike widths") of up to 134 microseconds are probably real. Assuming that the arc radiates RF throughout the discharge of solar cell coverglasses, the RF duration should then depend on the length or width of the arcing solar array and the plasma ion components from the arc-site.…”

Series DC Arc Simulation of Photovoltaic System Based on Habedank Model

“…Thus, a modified method to determine P 0 and U C needs to be proposed for the DC arc in PV systems. Since the arc variation time is on the order of microseconds [55], its variation time is negligible compared to the time required for electrode expansion and interval of MPPT action. Therefore, if small variation caused by irregular jumping of arc is ignored, the change of arc can be regarded as a transient state, during which the conductance of the arc is constant.…”

Rise Time and Peak Current Measurement of ESD Current from Air Discharges with Uncertainty Calculation

“…In [39], the results indicated that as temperature decreases, or pressure increases, the electrostatic Electronics 2022, 11, 2507 2 of 14 breakdown voltage increases, while in [40], the approach speed on spark length during air discharges with different temperature and humidity is examined. In a recent study [41], a model is constructed to make both the varied plasma velocities reported in the literature understandable, and also make predictions about the arc radio-frequency interference, contamination produced by the arcs, and the total charge in an arc possible.…”