Modeling of streamer-to-spark transitions in the first pulse and the post discharge stage

Abstract

The streamer-to-spark transition in a point-to-plane configuration in atmospheric pressure air is studied using a 2D–0D combined approach. A validated fluid code is used and improved to model the spark stage. 2D modeling of discharges at three different temperatures, 300, 600 and 800 K, are conducted; the spark transition occurs when the temperature reaches 800 K in the first pulse. A conservative criteria of spark transition temperature is proposed based on analytical solution and compared with experiments. Kinetics modeling of the post discharge stage is conducted with consistent input values extracted from the 2D model. Results show that the streamer-to-spark transition can be initiated at a lower temperature (600 K) and lower field (50–75 Td), and the long-lifetime O-atoms formed in previous pulses play an important role in ‘knocking off’ the electrons from negative charged species and maintaining the electron density in the post discharge stage. The dominating processes for electron production are electron detachment reactions from O 3 − , O 2 − and O−. The ionizations from excited species only accelerate the production of electrons when the plasma is already dense.

Morphology of positive ionization waves in atmospheric pressure air: influence of electrode set-up geometry

“…Recently, several experimental and numerical studies in point-to-plane geometry in air gaps of about 1 cm at atmospheric pressure have reported images of axisymmetric diffuse discharges with maximum radius of several centimeters as reviewed in Naidis et al (2018) and shown since then in Brisset et al (2019); Chng et al (2019); Tarasenko et al (2020); Tarasenko (2020); Chen et al (2020); Bourdon et al (2020); Babaeva and Naidis (2021); Zhu et al (2021). These discharges are obtained using high voltage pulses (with maximum voltages being five or ten times higher than classical steady-state breakdown levels) applied with sub-nanosecond and nanosecond rise times.…”

“…Then, the understanding of conditions in which a diffuse nanosecond positive ionization wave can be obtained in atmospheric pressure air is of particular interest. So far, the number of experimental and numerical studies on positive diffuse discharges in atmospheric pressure air remains limited (Naidis et al, 2018;Tardiveau et al, 2009;Pechereau et al, 2014;Babaeva and Naidis, 2016b;Babaeva and Naidis, 2016a;Marode et al, 2016;Tardiveau et al, 2016;Tarasenko et al, 2020;Chen et al, 2020;Bourdon et al, 2020;Babaeva and Naidis, 2021;Zhu et al, 2021). Rather good agreement between experiments and simulations has been obtained on discharge characteristics such as the maximum discharge radius and ionization front velocity as reviewed in Naidis et al (2018); Babaeva and Naidis (2021) and on the time evolutions of the electric field on the symmetry axis as shown at very early times of discharge propagation in Brisset et al (2019) and during the whole discharge propagation in the gap in Bourdon et al (2020); Zhu et al (2021).…”

“…Experimentally, Tardiveau et al (2016) have studied the influence of the tip radius in the range 10 to 200 µm on the discharge characteristics and have reported only A c c e p t e d M a n u s c r i p t a small influence on discharge morphology and time development. In most simulation works, simple shapes of point electrodes are used (sphere in Babaeva and Naidis (2016b); Babaeva and Naidis (2016a), rod ended by semi-sphere in Bourdon et al (2020), conical shape ended by a semi-sphere in Pechereau et al (2014), parabolic shape in Marode et al (2016); Brisset et al (2019) and conical shape ended by a hyperboloid electrode in Chen et al (2020)). Recently, in Zhu et al (2021), a more complex shape (combining a conical pin with a metal cylinder on a trapezoidal holder) has been considered to be as close as possible to experiments in Chng et al (2019).…”

Tailoring electric field signals of nonequilibrium discharges by the deep learning method and physical corrections

“…[ 40 ] It has been well validated that the evolution of a spark channel (and corresponding E/N value) can be well described by a volume‐averaged global model. [ 45 ]…”

“…[40] It has been well validated that the evolution of a spark channel (and corresponding E/N value) can be well described by a volume-averaged global model. [45] The second question is how to reproduce such specific E/N temporal profiles in real experiments? There is a gap between the voltage profile and the electric field temporal profile.…”