HR: 13:40h
AN: SM53C-01    [Abstracts]
TI: Interball Statistics of Bow Shock Energetic Ions
AU: Kudela, K
EM: kkudela@upjs.sk
AF: Institute of Experimental Physics, Slovak Aacdemy of Sciences, Watsonova 47, Kosice, 04353 Slovakia (Slovak Republic)
AU: * Chang, S
EM: shen.chang@msfc.nasa.gov
AF: Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 35899 United States
AU: * Chang, S
EM: shen.chang@msfc.nasa.gov
AF: National Space Science and Technology Center, 320 Sparkman Dr, Huntsville, AL 35805 United States
AB: Energetic ions observed by the Interball Tail spacecraft from August, 1995 through September, 2000 upstream from the Earth's bow shock are studied. Most of the time, energetic ion distribution is found to be nearly isotropic and less than 3% of the time for highly anisotropic distribution. We further investigated the dependence of ion flux and spectral slope on the solar wind density and velocity, $\theta_{Bn}$, and Kp index. Preliminary results reveal different patterns for the lower and higher energetic ions. For the diffuse events, the lower energetic component is better organized by the solar wind parameters and $\theta_{Bn}$. The spectral slope of ion energy spectrum shows some dependence on the solar wind velocity. These results are consistent with bow shock acceleration at the quasi-parallel shock for solar wind ions. However, the higher energetic ion flux is less dependent on the solar wind parameters and bow shock geometry. When energetic ion distribution is highly anisotropic, their flux becomes much better correlated with the Kp index. These results indicate that magnetospheric leakage dominates the higher energetic component. There are clearly indications that both shock acceleration and magnetospheric leakage contribute to the upstream energetic ions even for diffuse ion events. Their relative contribution is energy dependent.
DE: 2116 Energetic particles, planetary
DE: 2154 Planetary bow shocks
DE: 2716 Energetic particles, precipitating
DE: 2720 Energetic particles, trapped
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting