Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discharge convective instability as modifier of nonlinear hydrodynamic
  spectrum   Discharge source is considered as modifier of flow hydrodynamic spectrum.
Characteristic frequency of nonlinear spectrum and spectrum power were
determined under conditions of arc sliding discharge in supersonic flow. Two
stages of discharge were defined: sliding stage and still stage. It was found
that stage transition occurs due to convective instability of discharge.
Fraction of sliding stage in overall discharge duration is determined by
averaged current that is general stable discharge parameter. This phenomenon
gives opportunity to control power of pressure fluctuations spectrum.
Theoretical insight of field and hydrodynamic factors influencing on pulsations
frequency was achieved. Hydrodynamic resistance of discharge region and holding
cathode electric field turned out to be basic factors of frequency
modification. Corresponding experimental verification was taken. Basic
frequency law was determined for several discharge regimes.

30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph