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Electron heat flux instabilities in coronal holes: Implications for ion heating
Author(s) -
Markovskii S. A.,
Hollweg Joseph V.
Publication year - 2002
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 - 10.1029/2002gl015189
Subject(s) - solar wind , physics , coronal hole , heat flux , nanoflares , cyclotron , plasma , instability , coronal cloud , atomic physics , magnetic reconnection , flux (metallurgy) , corona (planetary geology) , computational physics , coronal mass ejection , astrophysics , mechanics , materials science , heat transfer , nuclear physics , astrobiology , metallurgy , venus
There is growing evidence that the heating of the ions in solar coronal holes and the resulting generation of the fast solar wind is due to cyclotron‐resonant damping of ion cyclotron waves. At the same time, the origin of these waves is not understood. In this paper, it is suggested that the waves in the proton cyclotron frequency range are generated by a plasma microinstability due to a heat flux coming from the Sun. A new view is used according to which heat flux is launched intermittently by small‐scale reconnection events (nanoflares) at the coronal base. This allows the heat flux to be sporadically large enough to drive the instabilities, while at the same time satisfying the time‐averaged energy requirements of the solar wind. It is shown that in a low‐beta coronal plasma an electrostatic heat‐flux instability has a comparable threshold and much greater growth rate than a shear Alfvén heat flux instability. The implications of these instabilities for the ion heating in the coronal holes are discussed.