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arXiv · 1004.1859

Estimated relations at a shock driven by a coronal mass ejection

M. Eselevich·V. Eselevich
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Abstract

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 Alfvén Mach number $M_A$ on shock wave strength $ρ_2/ρ_1$, measured at $R > 10R_\odot$ from the center of the Sun, to ideal MHD calculations suggests that the effective adiabatic index $γ$, 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, $M_A(ρ_2/ρ_1)$, 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.

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M. Eselevich, V. Eselevich. 2010-04-12. Estimated relations at a shock driven by a coronal mass ejection. https://arxiv.org/abs/1004.1859

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