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A magnetic cloud and a coronal mass ejection
Author(s) -
Burlaga L. F.,
Klein L.,
Sheeley N. R.,
Michels D. J.,
Howard R. A.,
Koomen M. J.,
Schwenn R.,
Rosenbauer H.
Publication year - 1982
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/gl009i012p01317
Subject(s) - magnetic cloud , coronal mass ejection , physics , magnetic field , solar wind , ecliptic , spacecraft , astronomy , astrophysics , quantum mechanics
An interplanetary magnetic cloud observed by the Helios 1 spacecraft was found to be associated with a coronal mass ejection observed by the NRL Solwind coronagraph on the spacecraft P78‐1. The magnetic cloud was observed on June 20, 1980 when Helios 1 was at 0.54 AU and nearly 90° west of the earth‐sun line. This was associated with a large loop‐like coronal mass ejection observed over the west limb on June 18, 1980, moving toward Helios 1. The speed of the front of the event at Helios 1 was (470 ± 10) km/s, which is close to the mean transit speed (∽ 500 km/s). The magnetic cloud was similar to others described in the literature: The magnetic field strength was higher than average; the density was relatively low; the magnetic pressure greatly exceeded the ion thermal pressure; and the magnetic field direction changed through the cloud by rotating parallel to a plane which was highly inclined with respect to the ecliptic.