Electrical and optical characteristics of a nanosecond pulsed electrical discharge in air in contact with a water droplet for various electrical conductivities
Bibliographic record
Abstract
Abstract Interactions between pulsed electrical discharges and liquid dielectric materials have emerged as a growing research field with interests in fundamental discharge physics and subsequent applications. Herein, we present an experimental study on the dynamics of nanosecond discharges in air in the presence of a water droplet with various electrical conductivities (EC) and at different applied voltages ( V a ). The discharges are characterized optically, by employing time-resolved ICCD imaging and optical emission spectroscopy, and electrically, by acquiring the current–voltage waveforms for every discharge. The results show that three modes of discharge can be obtained: i) streamer discharge between the cathode and the droplet, ii) streamer discharge between the cathode and the droplet as well as between the anode and the droplet, and iii) spark discharge that connects the two electrodes and propagates over the droplet. We find that the probability to obtain one of the three discharge modes is strongly related to the droplet’s EC and V a . Although the streamer’s ignition is relatively insensitive to EC, its transition to a spark can be finely controlled by the droplet’s EC. Time-resolved ICCD images show that the discharge initiates in the gap between the cathode and the droplet, followed by ignition between the anode/ground electrode and the droplet. Next, an extinction phase is observed before the ignition of a secondary streamer. Depending on the conditions, the discharge may transition to a spark, that is a channel with high emission intensity. We find that the duration of each stage of discharge propagation and the corresponding emission (path and intensity) are sensitive to the droplet’s EC. Finally, emissions from streamers (primary and secondary) and from sparks are analyzed using optical spectroscopy. We find that the emission from the streamers is dominated by the second positive system of N 2 , and that the droplet’s EC does not significantly affect the emission spectra nor the estimated rotational temperature of N 2 .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".