Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: DC high voltage to drive helium plasma jet comprised of repetitive
  streamer breakdowns   This paper demonstrates and studies helium atmospheric pressure plasma jet
comprised of series of repetitive streamer breakdowns, which is driven by a
pure DC high voltage (auto-oscillations). Repetition frequency of the
breakdowns is governed by the geometry of discharge electrodes/surroundings and
gas flow rate. Each next streamer is initiated when the electric field on the
anode tip recovers after the previous breakdown and reaches the breakdown
threshold value of about 2.5 kV/cm. Repetition frequency of the streamer
breakdowns excited using this principle can be simply tuned by reconfiguring
the discharge electrode geometry. This custom-designed type of the helium
plasma jet, which operates on the DC high voltage and is comprised of the
series of the repetitive streamer breakdowns at frequency about 13 kHz, is
demonstrated.

2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc