Impact of the electrode proximity on the streamer breakdown and development of pulsed dielectric barrier discharges

Abstract

The impact of the electrode proximity on the streamer breakdown and development of pulsed-driven dielectric barrier discharges (DBDs) in a single-filament arrangement has been investigated in a gas mixture of 0.1 vol% O2 in N2 at 0.6 bar and 1.0 bar. The gap distance was varied from 0.5 mm to 1.5 mm, and the applied voltage was adapted correspondingly to create comparable breakdown conditions in the gap. The development of the DBDs was recorded by an iCCD and a streak camera system, while fast electrical measurements provided insight into discharge characteristics such as the transferred charge and consumed energy. The results demonstrate that breakdown in a smaller gap is characterised by a slower streamer propagation but a significantly higher acceleration. It can therefore be concluded that the proximity of the cathode has a strong impact on the characteristics of the streamer breakdown. However, after the streamer has crossed the gap, the discharge structure in front of the anode was found to be the same independent of the actual gap distance.

Exploring the mechanisms leading to diffuse and filamentary modes in dielectric barrier discharges in N$$_2$$ with N$$_2$$O admixtures

“…using the first time derivative of the applied voltage U . The value for C tot was found to be approximately 0.2 pF, which is in good agreement with the total capacitance obtained for pulsed operation in the same arrangement [34]. The discharge current of the APTD can only be seen as minuscule "humps'" on the sinusoidal curve (indicated by circles in the top row of Fig.…”

The longitudinal energy spread of ion beams extracted from an electron cyclotron resonance ion source

“…The motivation to study the longitudinal energy spread of the ion beams extracted from the LPSC CB stems from the desire to improve the understanding of the 1+ ion capture process into the ECRIS plasma. In particular, the goal is a comparison of the so-called Δ𝑉-curves of the high charge state ions reflecting the capture efficiency and the energy spread of the N+ ion beams extracted from the CB, possibly challenging the prevailing model for the ion capture based on slowing down in consecutive ion-ion collisions and requiring to match the velocity of the incident ions to the average velocity of the plasma ions [27,28]. For this purpose, and to measure the longitudinal energy spread due to the plasma characteristics (not due to the extraction conditions), only the ions closest to the beam axis are to be considered.…”

Characteristics of high-repetition-rate bipolar pulse DBD under various electrical conditions in atmospheric-pressure air

“…The discharge characteristics and ozone generation were analyzed at a flow rate of 1 l min −1 for each of the following: voltage (11-15 kV), frequency (12)(13)(14)(15)(16)(17)(18)(19)(20), and duty ratio (15%-30%). Except for the case where the initial instantaneous value was analyzed, all the discharge characteristics, such as the discharge current and Lissajous curve, were analyzed using the 512-average value function inside the oscilloscope.…”

“…When these regions are combined in a parallel connection, the capacitance value when a discharge occurs is represented by C d . These series of processes are shown in equations ( 18)- (20). At this time, equation ( 20) was changed to equation ( 14) to calculate the effective area, because the latter term representing the non-discharge region in equation ( 20) is much smaller than the former term and is ignored.…”

“…According to Wubs et al [20], a higher applied voltage, along with a steeper voltage slope, results in a higher breakdown voltage and a higher electrical current. However, in this case, it causes an increase in preionization and affects the next discharge by lowering the breakdown voltage and decreasing the current peak in the unipolar pulse DBD [20].…”