HR: 11:35h
AN: SH12B-06    [Abstracts]
TI: Acceleration at the termination shocks: the pitch-angle perspective
AU: * Florinski, V
EM: vflorins@ucr.edu
AF: University of California, Riverside, 900 University Avenue, Riverside, CA 92521, United States
AU: Decker, R B
EM: robert.decker@jhuapl.edu
AF: Johns Hopkins University, 11100 Johns Hopkins Rd., Laurel, MD 20723, United States
AB: We use a recently developed anisotropic transport model to investigate observed pitch-angle distributions (PADs) of energetic protons near the solar wind termination shock. Voyager data is represented in the form of expansion in spherical harmonics in the frame aligned with the measured mean magnetic field, permitting a direct comparison with the model. We find that observed PADs are consistent with model predictions for particle acceleration at a highly oblique shock wave. The termination shock obliquity angle is derived from first-order anisotropy measurements. Additionally, second-order anisotropy is used to obtain energy dependence of the particle mean free paths. We demonstrate that analyzing second-order anisotropy is crucial for interpreting data correctly. It is also shown that certain measured distributions characterized by anomalously large second moments can be interpreted as oppositely propagating beams in regions multiply-connected to the spacecraft.
DE: 2114 Energetic particles (7514)
DE: 2124 Heliopause and solar wind termination
DE: 2152 Pickup ions
DE: 7807 Charged particle motion and acceleration
DE: 7859 Transport processes
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting