HR: 0830h
AN: SH21B-0112    [PDF]
TI: Intermittent coronal heating due to heat flux generated ion cyclotron waves
AU: * Markovskii, S A
EM: Sergei.Markovskii@unh.edu
AF: Space Science Center, University of New Hampshire, Morse Hall, Durham, NH 03824 United States
AU: Hollweg, J V
EM: joe.hollweg@unh.edu
AF: Space Science Center, University of New Hampshire, Morse Hall, Durham, NH 03824 United States
AB: Recently, we suggested [Hollweg and Markovskii, JGR, 107, No. 6, 2002; Markovskii and Hollweg, GRL, 29, No. 17, 2002] that the source of ion heating in coronal holes is small-scale reconnection events (microflares) at the coronal base. The microflares launch intermittent heat flux up into the corona exciting ion cyclotron waves through a plasma microinstability. The ions are heated by these waves during the microflare bursts and then evolve with no energy input between the bursts. We show that the structure of the proton distribution in the relatively long time periods between the microflares is determined by collisions at small heliocentric distances. At greater distances, the collisional processes are replaced by similar processes due to secondary instabilities. These are excited by the distortion of the distribution under the action of the mirror force. At the same time, the heating during the microflare bursts is not considerably affected either by the collisions or by the secondary instabilities, because of the short duration of the bursts. The overall coronal heating by this mechanism is a summed effect of all microflare bursts during the expansion time of the solar wind and adiabatic cooling between the microflares. Our calculations for the collision-dominated region suggest that the overall heating is efficient enough to account for the acceleration of the fast solar wind in this region. Further development of the model including the collisionless region will be reported elsewhere.
DE: 2169 Sources of the solar wind
DE: 7511 Coronal holes
DE: 7827 Kinetic and MHD theory
DE: 7867 Wave/particle interactions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting