Abstract
An analysis of SOHO/LASCO C3 data shows that there are discontinuities in the radial profiles of the plasma density within limited regions in front of each of ten coronal mass ejections, which represent shocks. The shock velocities in various events reach V ≈ 800–2500 km/s. A comparison of the dependence of the AlfvenicMach numberM A on the shock strength ρ 2/ρ 1 detected at distancesR > 10R⊙ from the center of the Sun with calculations carried out using ideal magnetic hydrodynamics shows that the effective ratio of specific heats γ describing processes inside the shock front varies from 2 to 5/3 (ρ 1 and ρ 2 are the densities in front of and behind the shock, and R⊙ is the solar radius). This corresponds to an effective number of degrees of freedom between two and three. A similar dependenceMA(ρ 2 /ρ 1) was found for near-Earth bow shocks and interplanetary collisionless shocks. These features support the hypothesis that the studied discontinuities preceding coronal mass ejections are collisionless shocks.
Similar content being viewed by others
References
A. Vourlidas, S. T. Wu, A. H. Wang, et al., Astrophys. J. 598, 1392 (2003).
M. V. Eselevich and V. G. Eselevich, Astron. Zh. 84, 1046 (2007) [Astron. Rep. 51, 947 (2007)].
W. B. Manchester, A. Vourlidas, G. Tóth, et al., Astrophys. J. 648, 1448 (2008).
M. V. Eselevich and V. G. Eselevich, Geophys. Res. Lett. 35, L22105 (2008).
V. Ontiveros and A. Vourlidas, Astrophys. J. 693, 267 (2009).
M. V. Eselevich, Astron. Zh. 87, 197 (2010) [Astron. Rep. 54, 173 (2010)].
G. Mann, H. Aurass, A. Klassen, et al., in Plasma Dynamics and Diagnostics in the Solar Transition Region and Corona, ESA SP-446 (ESA, Paris, France, 1999), p. 477.
G. Mann, F. Jansen, R. J. MacDowall, et al., Astron. Astrophys. 348, 614 (1999).
G. E. Brueckner, R. A. Howard, M. J. Koomen, et al., Solar Phys. 162, 357 (1995).
A. R. Kantrowitz and H. E. Petschec, in Plasma Physics in Theory and Application, Ed. by W. B. Kunkel (McGraw-Hill, New York, 1966).
C. F. Kennel, J. P. Edmiston, and T. Hada, AQuarter Century of Collisionless Shock Research (Department of Physics, Univ. of California, Los Angeles, CA, 1984).
H. Cremades and V. Bothmer, Astron. Astrophys. 422, 307 (2004).
S. Yashiro, N. Gopalswamy, G. Michalek, et al., J. Geophys. Res. 109, A07105 (2004).
Y.-M. Wang, N. R. Sheeley, D. G. Socker, et al., J. Geophys. Res. 105, 25133 (2000).
K. Saito, A. I. Poland, and R. H. Munro, Solar Phys. 55, 121 (1977).
D. E. Billing, A Guide to the Solar Corona (Academic Press, New York, 1966), p. 150.
G. Zimbardo, in Twelfth International Solar Wind Conference, AIP Conf. Proc. 1216, 52 (2010).
R. Z. Sagdeev, in Questions of Plasma Theory, Ed. by M. A. Leontovich (Atomizdat, Moscow, 1964), p. 20 [in Russian].
G. N. Zastenker, N. L. Borodkova, O. L. Vaisberg, et al., Preprint Space Res. Inst. No. 841 (Space Research Inst., Moscow, 1983).
V. Formisano, P. C. Hedgecoc, G. Moreno, et al., J. Geophys. Res. 78, 3731 (1973).
E. W. Greenstadt, C. T. Russel, J. T. Gosling, et al., J. Geophys. Res. 85, 2124 (1980).
S. J. Bame, J. R. Asbridge, J. T. Gosling, et al., Space Sci. Rev. 23, 75 (1979).
S. D. Bale, M. A. Balikhin, and T. S. Horbury, Space Sci. Rev. 118, 161 (2005).
T. L. Totten, J.W. Freeman, and S. Arya, J. Geophys. Res. 100, 13 (1995).
E. Priest, Solar Magnetohydrodynamics (Gordon and Breach, London, 1981; Mir, Moscow, 1985).
Author information
Authors and Affiliations
Additional information
Original Russian Text © M.V. Eselevich, V.G. Eselevich, 2011, published in Astronomicheskii Zhurnal, 2011, Vol. 88, No. 4, pp. 393–408
Rights and permissions
About this article
Cite this article
Eselevich, M.V., Eselevich, V.G. Relations estimated at shock discontinuities excited by coronal mass ejections. Astron. Rep. 55, 359–373 (2011). https://doi.org/10.1134/S1063772911020028
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1063772911020028