HR: 0830h
AN: SH11C-1122    [PDF]
TI: A kinetic theory of energetic particle transport in intermediate-scale compressive velocity fluctuations associated with ion-acoustic waves
AU: * le Roux, J A
EM: Jakobus@ucrac1.ucr.edu
AF: Institute of Geophysics & Planetary Physics, University of California, Riverside, CA 92521
AU: Fichtner, H
EM: hf@tp4.ruhr-uni-bochum.ed
AF: Theoretische Physik IV, Weltraum-und Astrophysik, Ruhr-Universitaet Bochum, Bochum, D-44780 Germany
AU: Webb, G M
EM: gmwebb@citrus.ucr.edu
AF: Institute of Geophysics & Planetary Physics, University of California, Riverside, CA 92521
AU: Zank, G P
EM: zank@ucrac1.ucr.edu
AF: Institute of Geophysics & Planetary Physics, University of California, Riverside, CA 92521
AB: Linear Vlasov kinetic theory indicates that ion-acoustic waves might be weakly damped at low latitudes in the solar wind in a propagation direction along the background magnetic field. The existence of a field-aligned ion-acoustic mode is also supported by nearly incompressible MHD theory of the solar wind. A kinetic pitch-angle dependent transport theory was developed to explore how energetic charged particles respond to the small-amplitude compressive intermediate-scale velocity fluctuations associated with undamped ion-acoustic waves propagating along the large-scale magnetic field. Note that the theory is extended beyond standard quasi-linear theory in the sense that it is assumed in the theory that the particles are already scattering on small-scale MHD fluctuations when interacting with intermediate-scale velocity fluctuations. This coupling between small and intermediate scales in the limit of nearly isotropic particle distributions results in compound parallel spatial diffusion with particle scattering taking place on both small and intermediate scales. Of interest is that the theory implies that diffusive compression particle acceleration can occur whereby suprathermal particles such as pickup ions might acquire a distribution function with a power law spectrum in the quiet low-latitude solar wind.
DE: 2149 MHD waves and turbulence
DE: 2152 Pickup ions
DE: 7859 Transport processes
DE: 7867 Wave/particle interactions
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting