In this work, the propagation of the surface ionization wave (SIW) in the nanosecond pulsed surface dielectric barrier discharge with different dielectric materials and pulse repetition rates is investigated. The current waveforms at different locations along the route of the SIW propagation are obtained, based on a specially designed ground strip array geometry. The temporal evolution and spatial distribution of the electric field during the SIW propagation are measured by using the electric field induced second harmonic (EFISH) generation method. The distribution of the residual surface potential after the discharge is mapped with a Kelvin electrostatic probe, which verifies both the existence of the residual electric field and its opposite direction to that during the SIW propagation. It is found that with the dielectric material on which the surface charges decay faster, there are the well-pronounced primary and secondary SIWs with a higher velocity on the voltage rising edge and both the peak current and the peak electric field are also higher, with a less spatial attenuation along the SIW propagation route. It is demonstrated that the residual surface charges with the same polarity as the high-voltage pulse suppress the development of the surface ionization wave.

https://iopscience.iop.org/article/10.1088/1361-6595/ab7854/pdf

Surface ionization wave propagation in the nanosecond pulsed surface dielectric barrier discharge: the influence of dielectric material and pulse repetition rate

https://iopscience.iop.org/article/10.1088/1361-6595/ab094c/pdf

Atmospheric-pressure pulsed plasma actuators for flow control: shock wave and vortex characteristics

Repetitively pulsed gas volume and dielectric surface discharges have gained growing attention because of peculiar and exciting physics phenomena, high efficiency, high reactivity, and potential to obtain conventionally unachievable plasma properties. Nevertheless, incomplete understanding of fundamental mechanisms renders the repetitively pulsed discharge far less predictable and controllable, where the inherent memory effect and the discharge mode transition are universal challenges. In this topical review, the authors will explore the macroscopic characteristics of the gas gap breakdown and the surface flashover, state-of-the-art mechanisms and dominant agents of discharge memory effects, operation regimes and transitions of the discharge mode, and how waveform parameters affect the pulsed discharge properties. Challenges and potential approaches for further understanding the memory effect and the discharge mode transition in the repetitively pulsed discharge are discussed.

Repetitively pulsed gas discharges: memory effect and discharge mode transition

Cold atmospheric-pressure plasma jet generates rich reactive species including reactive oxygen species and reactive nitrogen species with gas temperature close to or at room temperature, which is very attractive for applications such as plasma medicine. However, under one atmospheric pressure, due to the high electron–neutral particles collision frequency (1011–12/s), it is difficult to generate atmospheric pressure plasma while keeping the gas temperature close to or at room temperature. Furthermore, when air rather than noble gases is used as working gas, due to the low energy levels of rotational and vibrational states of nitrogen and oxygen, it becomes extremely challenging to generate cold atmospheric pressure air plasma jet (CAAP-J) with gas temperature close to or at room temperature. Fortunately, after decades of research, several CAAP-Js have been reported. In this review, the state-of-the-art of the development of CAAP-Js is presented. The CAAP-Js are grouped into six categories based on their electrode configuration. A brief discussion on each group of the CAAP-Js is presented. Moreover, the physics of CAAP-Js is discussed, including the dynamics, the striation phenomenon, the temporal behavior of plasma parameters, and the nonequilibrium characteristic of CAAP-Js. Furthermore, the measurements of the reactive species generated by CAAP-Js are briefly reviewed. Finally, discussions and perspective of future research on CAAP-Js are presented.

Cold atmospheric-pressure air plasma jet: Physics and opportunities

Transitions between the streamer and spark modes affect the stability of gas–liquid discharges, limiting their practical applications, while the nature of such transitions is poorly understood. Here we clarify the often neglected effect of a dielectric on the gas–liquid discharge stability, using direct and indirect grounding configurations. Discharge modes and plasma characteristics in these two configurations are investigated. The discharge appears in a transient spark mode in the direct grounding while in a streamer mode in the indirect case. It is shown that the dielectric significantly improves the discharge stability. The gas temperature and electron density in the transient spark are 380 K and 1017/cm3 with a 30 kV pulse voltage, respectively, which are higher than those in the streamer mode.

Mode transition and plasma characteristics of nanosecond pulse gas–liquid discharge: Effect of grounding configuration

Plasma synthetic jet (PSJ) has a wide application prospect in flow separation suppression and boundary layer control. Comparing with traditional control methods, synchronous discharges of PSJ with high repetition frequency and high energy could achieve a better flow control effect because it can meet multi-angle, wide-range and long-time flow control requirements. In this paper, a microsecond-pulse power supply for synchronous discharges of three plasma synthetic jet actuators (PSJA) is developed. Parameters of output pulses are as follows: the maximum voltage pulse is 10 kV, the pulse repetition rate is 1000 Hz and the full width is 15 μs. The generator can withstand a discharge current with an amplitude of 320 A and a discharge energy of 150 mJ. The electrical characteristics of the synchronous discharges of PSJAs including the voltage-current waveforms, discharge images and Schlieren images are investigated. The experimental result shows that the microsecond-pulse generator could sustain three discharge channels in PSJAs when the output voltage is 10 kV. These discharge channels have preferable performance in synchronicity when the repetition frequency is 1000 Hz. Furthermore, the Schlieren images show that the power supply can sustain three PSJAs with a maximum jet velocity of up to 150 m/s.

A pulsed generator for synchronous discharges of high-energy plasma synthetic jet actuators

The invention discloses a high-voltage pulse power supply for the synchronous discharge of multiple spark plasma synthetic jet actuators, and the power supply comprises a main circuit module which is used for generating multiple synchronous negative high-voltage pulses; a control circuit module which is used for generating an IGBT switch drive signal; a power supply module which is used for supplying power to a main circuit module and a control circuit module; and a protection circuit module, wherein a thyristor switch in the protection circuit module is connected with an IGBT switch in the control circuit module The power supply module is connected with the main circuit module and the control circuit module The protection circuit module is connected with the main circuit module and the control circuit module The control circuit module is connected with the main circuit module The beneficial effects of the invention are that the structure is simple and compact; the plasma synthetic jet speed is high and the work efficiency is high; the power supply can output multiple 10kV negative high-voltage pulses synchronously to achieve the synchronous excitation of a plurality of spark plasma synthetic jet actuators, achieves the synchronous discharge of the plurality of spark plasma synthetic jet actuators, and enables the discharge current of a single spark plasma synthetic jet actuator to be greater than 100A

High-voltage pulse power supply for synchronous discharge of multiple spark plasma synthetic jet actuators

The invention discloses a plasma synthesis jet flow serial connection discharge device based on a Marx generator. The negative pole of a direct current source is grounded, and the positive pole of the direct current source is connected with one end of a charge resistor; the other end of the charge resistor is connected with the positive poles of multiple charge diodes; the negative poles of the multiple charge diodes are connected with one ends of multiple charge capacitors; the other ends of the multiple charge capacitors are connected with the positive poles of multiple discharge diodes; multiple plasma synthesis jet flow exciters are connected to the negative poles of the charge diodes and the negative poles of the discharge diodes in parallel; a discharge resistor is arranged between two discharge diodes; the negative poles of the discharge diodes are grounded; ground electrodes of the plasma synthesis jet flow exciters are grounded; and two ends of a load are connected to the positive pole of the first discharge diode and the negative pole of the last discharge diode in parallel. The plasma synthesis jet flow serial connection discharge device has the following beneficial effects: when the multiple plasma synthesis jet flow exciters are serially connected to synchronously discharge, multi-way superposition pulses are formed at two ends of the load, so that the multi-angle and wide-range flow control can be realized in high-speed flowing field control field, and the high-voltage discharge experimental study can be performed.

Plasma synthesis jet flow serial connection discharge device based on Marx generator

The invention discloses a device and a method for synchronous discharge of multiple plasma synthetic jet actuators. The method comprises the following steps: providing a power source for a pulse generator module by a first power supply, and using a pulse generator to provide a driving signal for the switch of a switching synchronization drive circuit; providing a power source for the switching synchronization drive circuit by a second power supply, and using the switching synchronization drive circuit to provide a synchronous trigger signal for switches of multiple high-voltage pulse circuits; providing a power source for the high-voltage pulse circuits comprising multiple high-voltage pulse circuit modules by a third power supply, and enabling the high-voltage pulse circuits to be matched with the plasma synthetic jet actuators to generate multipath plasma synthetic jet flows. The device and the method have the beneficial effects that the multiple plasma synthetic jet actuators synchronously run, the discharge current exceeds 100A, and a powerful synthetic jet can be generated; the device is compact in structure and is capable of running for a long time.

Luo Zhenbing

Papers

Atmospheric-pressure pulsed plasma actuators for flow control: shock wave and vortex characteristics

A pulsed generator for synchronous discharges of high-energy plasma synthetic jet actuators

High-voltage pulse power supply for synchronous discharge of multiple spark plasma synthetic jet actuators

Plasma synthesis jet flow serial connection discharge device based on Marx generator

Device and method for synchronous discharge of multiple plasma synthetic jet actuators