HR: 0830h
AN: SH31A-1087    [PDF]
TI: Heating and Acceleration due to Lower Hybrid Waves in Magnetic Reconnection Regions
AU: * Cairns, I H
EM: cairns@physics.usyd.edu.au
AF: University of Sydney, School of Physics, Sydney, NSW 2006 Australia
AB: Magnetic reconnection is widely believed to produce significant plasma heating and acceleration of particles to high energies. Little agreement exists as to how this is done. Here it is shown that a critical theoretical difficulty is posed by the following: (1) Observations of solar flares suggest that $\approx 10 - 50 %$ of the available magnetic energy is channelled into semi-relativistic electrons and protons, plus plasma heating to over $10^{6}$~K. (2) Wind spacecraft observations of reconnection in Earth's magnetotail show that electrons are accelerated to speeds $\approx c/2$, but contain less than $10^{-10} %$ of the total electron energy. (3) Why are the acceleration efficiencies many orders of magnitude different when the Alfven speeds and plasma temperatures are similar? Lower hybrid waves are common in Hall-MHD simulations and Wind observations of reconnection. It is suggested here that lower hybrid waves are important in producing electron acceleration and ion heating in reconnection regions, via so-called ``lower hybrid drive''. Analytic theory is used to support this suggestion and to argue that lower hybrid drive should be much more efficient under solar conditions.
DE: 2744 Magnetotail
DE: 7519 Flares
DE: 7807 Charged particle motion and acceleration
DE: 7835 Magnetic reconnection
DE: 7867 Wave/particle interactions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting