Transient spark: a dc-driven repetitively pulsed discharge and its control by electric circuit parameters

Abstract

The paper presents an analysis of electrical characteristics of streamer-to-spark transition discharge in air at atmospheric pressure named transient spark (TS). The TS is applicable for flue gas cleaning or bio-decontamination and has potential in plasma shielding, combustion and flow control applications. Despite the dc applied voltage, TS has a pulsed character with short (∼10-100 ns) high current (>1 A) pulses, with repetitive frequencies 1-20 kHz. Estimation of the temporal evolution of electron density shows that n e ≈ 10 16 cm −3 at maximum and ∼10 11 cm −3 on average are reached using relatively low power delivered to the plasma (0.2-3 W). Thanks to the high repetition frequency, n e between two current pulses does not fall below a critical value and therefore plasma exists during the whole time. A detailed analysis of the TS control by electrical circuit parameters is presented. With appropriate circuit components, the current pulse tail (>1 mA) can be extended and the electron density can be held above ∼10 13 cm −3 for several tens of µs.

Ionic wind measurements on multi-tip plasma actuators

“…In general, the sparks are visible to the naked eye but they can also be recorded as short and strong current pulses, in the order of 1A and more. The power supply can not afford a permanent transition to the arc regime, so that this phenomenon can be described as a 'transient spark' [8], sustained only by the occasional complete discharge of the circuit capacity. The stability of a corona under steady working conditions can be quantified by reporting the time Δt between consecutive transient sparks as in figure 4: this figure is obtained from the histograms of the Δt measured along tests including hundredth of events for a set of actuators of sharpness growing from r = 0 to 4, namely C1,4,5,9,11 and 12.…”

Transient Processes During Formation of a Steady-State Glow Discharge in Air

“…However, this capacitance is inevitably available in the electric circuit (even in the absence of the connecting cable, this is a stray capacitance of the gap and of the connecting wires). In the transient processes, the capacitance C starts playing an essential role [27]- [29], [31], [34], [35]. For example, in the course of accident transition from glow to spark [27] or from corona to spark [31], [34], [35], just the energy stored in the capacitance is expended for formation of spark channel.…”

“…In the transient processes, the capacitance C starts playing an essential role [27]- [29], [31], [34], [35]. For example, in the course of accident transition from glow to spark [27] or from corona to spark [31], [34], [35], just the energy stored in the capacitance is expended for formation of spark channel. Similarly, the capacitance C determines a process of the very first breakdown in the gap and subsequent discharge behavior [27]- [29].…”

“…This effect typically appears at a time scale of 100 µs [27]- [29]. 0093-3813/$31.00 © 2012 IEEE However, the aforementioned applications often use the discharge regimes when, due to the glow-to-spark transitions, the short current pulses with a duration of about 100 ns are superimposed on a steady-state glow-type discharge plasma [20], [24]- [31]. In some cases, the so-called plasma bullets of short duration can propagate over the plasma plume [12], [32], [33].…”

Low-Current Plasmatron as a Source of Nitrogen Oxide Molecules

“…For instance, a corona discharge can be accompanied by the short current pulses or can be transformed into glow discharge [7]- [11]. A characteristic property of the glow discharge at a high pressure is the socalled glow-to-spark transition [9]- [14]. This means that the discharge burns in a glow regime only during a limited time, after which an accident transition to spark can occur.…”