Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Propagation of Relativistic Shock Wave Induced by Laser Spark in
  Quiescent Air   Laser-induced breakdown has shown many potential applications in the various
field of science and engineering. As the breakdown occurs in gas or aerosol, a
rapid hydrodynamic expansion as shock (blast) wave initiated from the
deposition location. The nature of the shock wave is one of the controlling
factors in many physical processes; unfortunately, its nature has still not
been clearly understood. In this study, an error was found during the
calculation of shock wave properties with the classical non-relativistic
approach. The error in calculation was due to the initial relativistic
propagation of high-temperature plasma. Initially, the plasma and shock wave
travel together with higher acceleration up to the point of inflation, and in
later time shockwave dissociate itself from the plasma. However, this
accelerating effect is neglected in the earlier studies. To address the
spontaneous accelerating and deaccelerating nature of the shock wave, the
theoretical details of the relativistic approach of shock wave propagation is
presented.

30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol