HR: 17:00h
AN: SH12C-05    [PDF]
TI: Anomalous-Cosmic-Ray and Plasma Signatures of the Termination Shock
AU: * Jokipii, J R
EM: jokipii@lpl.arizona.edu
AF: Dept of Planetary Sciences and Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721 United States
AU: Giacalone, J
EM: giacalone@lpl.arizona.edu
AF: Dept of Planetary Sciences and Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721 United States
AU: Kota, J
EM: kota@lpl.arizona.edu
AF: Dept of Planetary Sciences and Lunar and Planetary Lab, University of Arizona, Tucson, AZ 85721 United States
AB: We consider the response of anomalous cosmic rays (ACR) and the solar-wind plasma to a transient radial incursion of the solar-wind termination shock, in the context of recent Voyager observations. Such an incursion is likely to {\it not} be global and have limited extent in the transverse directions (latitude and longitude). We find that the (ACR) spectrum and anisotropy have temporal variations which depend on the time and transverse spatial scale of the radial incursion, its speed, and the energetic-particle transport coefficients. For reasonable parameters, the energy spectrum of the very-low-energy particles shows the largest effect, and the spectrum of the higher-energy particles the least. The transverse component of the heliospheric magnetic field must increase by a factor equal to the ratio of preshock to post-shock solar wind speed. Finally, the shock-accelerated energetic-particle anisotropies near, but upstream of the shock will have a signficant {\it diffusive} anistropy comparable and opposite to the Compton-Getting anisotropy. We conclude that the ACR spectrum and anisotropies expected at or near a shock crossing may be consistent with the observed spectra if one considers the likely case of transient,localized incursions of the termination shock.
DE: 2104 Cosmic rays
DE: 2114 Energetic particles, heliospheric (7514)
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting