Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Estimated relations at a shock driven by a coronal mass ejection   Analysis of SOHO/LASCO C3 data reveals a discontinuity, interpreted as a
shock wave, in plasma density radial profiles in a restricted region ahead of
each of ten selected coronal mass ejections (CME) along their travel
directions. In various events, shock wave velocity $V\approx$ 800-2500 km
s$^{-1}$. Comparing the dependence of Alfv\'{e}n Mach number $M_A$ on shock
wave strength $\rho_2/\rho_1$, measured at $R > 10R_\odot$ from the center of
the Sun, to ideal MHD calculations suggests that the effective adiabatic index
$\gamma$, characterizing the processes inside the shock front, is largely
between 2 and 5/3. This corresponds to the effective number of degrees of
freedom of motion 2 to 3. A similar dependence, $M_A(\rho_2/\rho_1)$, was
derived for the Earth's bow shock and interplanetary collisionless shock waves.
All this supports the assumption that the discontinuities in front of CMEs are
collisionless shock waves.

33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn