HR: 1340h
AN: SM33C-0468    [Abstracts]
TI: Electron Energisation Driven by Lower Hybrid Waves in Current Sheets and Magnetic Reconnection Regions.
AU: McMillan, B F
EM: mcmillan@physics.usyd.edu.au
AF: School of Physics, The University of Sydney, Sydney, NSW 2006 Australia
AU: * Cairns, I H
EM: cairns@physics.usyd.edu.au
AF: School of Physics, The University of Sydney, Sydney, NSW 2006 Australia
AB: Two new models for electron acceleration relevant to magnetic reconnection regions are developed analytically, tested using proof-of-principle quasilinear simulations, and evaluated in terms of qualitative consistency with observations of reconnection in Earth's magnetotail and the solar corona. Both models involve lower hybrid (LH) waves stochastically accelerating electrons parallel to the magnetic field by the Cherenkov resonance (LH drive or LHD). In the first model, wave-particle interaction with LH waves produced by the lower hybrid drift instability (LHDI) is considered as a mechanism for parallel electron acceleration from thermal to highly superthermal and even relativistic energies. We demonstrate that the observations in Earth's magnetotail and the solar corona (parallel acceleration favoured for low plasma beta) are qualitatively consistent with resonant LH wave-particle interactions. We use quasilinear simulations to explore the agreement semi-quantitatively: a spectrum of LH turbulence produced by LHDI and with levels obtained from particle simulations by Daughton (Phys. Plasmas, 10, 3103, 2003) is shown to produce an electron tail to about 20 electron thermal speeds in ≈ 600 lower hybrid times. In the second model, we consider LH waves produced by an oblique Buneman instability in plasmas with strong field aligned currents. In low β plasmas, with or without parallel E fields, we use quasilinear simulations to show that LH waves grow even for electron distributions stable to the (parallel) Buneman instability, and accelerate electrons parallel to B very rapidly. The quasilinear diffusion via LH waves can release almost all of the available drift energy, and produce stronger electron acceleration and heating than the Buneman instability alone.
DE: 2483 Wave/particle interactions (7867)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2772 Plasma waves and instabilities (2471)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005