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On formation of a shock wave in front of a coronal mass ejection with velocity exceeding the critical one
Author(s) -
Eselevich M. V.,
Eselevich V. G.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035482
Subject(s) - physics , discontinuity (linguistics) , front (military) , coronal mass ejection , shock wave , shock (circulatory) , corona (planetary geology) , astrophysics , magnetohydrodynamics , plasma , shock front , brightness , coronal plane , mechanics , astronomy , solar wind , meteorology , nuclear physics , medicine , mathematical analysis , mathematics , astrobiology , venus , radiology
It is shown that in front of a coronal mass ejection, having a velocity u lower than the critical u C relative to the surrounding coronal plasma, there is a disturbed region expended along a direction of the CME propagation. The time difference brightness (plasma density) in the disturbed region smoothly decreases to larger distances in front of the CME. A discontinuity forms at u higher than u C in the disturbed region front part in radial distributions of the difference brightness. Since the u C value is close to the local fast‐mode MHD velocity, which in corona approximately equal to the Alfven one, the formation of such a discontinuity when u C is exceeded may be identified with the formation of a shock wave.