HR: 11:35h
AN: SM52A-06    [Abstracts]
TI: MLT dependence of the spectral characteristics of energetic ions near the Earth's cusps
AU: * Friedel, R H
EM: friedel@lanl.gov
AF: Los Alamos National Laboratory Space Atmospheric Sciences, MS D466, Los Alamos, NM 87544 United States
AU: Trattner, K J
EM: trattner@mail.spasci.com
AF: Lockheed Martin, ADCS B255 3251 Hanover St, Palo Alto, CA 94304-1191 United States
AU: Fuselier, S
EM: fuselier@spasci.com
AF: Lockheed Martin, ADCS B255 3251 Hanover St, Palo Alto, CA 94304-1191 United States
AB: There has been much recent discussion of the role and origin of cusp energetic ions (CEP). Multiple origin theories have been entertained in the past (quasi-parallel bow shock acceleration, magnetospheric, or in situ heating) - and it has been difficult to obtain a clear differentiation between these sources since we in principle cannot ascertain where an individual ion comes from. In this study we aim to examine the role of the trapped magnetospheric ion population as a possible source for the high energy tail of CEPs which is not well explained by the quasi-parallel bow shock mechanism. It is well known that magnetospheric ion drift patterns intersect the dayside and flank magnetopause on the duskside There, these ions have access to the field lines which ultimately become cusp field lines. Ions injected over a wide local time range drift to the dusk side on rather thin shells. 10 keV ions injected over the entire night side escape the magnetosphere on the day side between about noon and 1600 LT. 100 keV ions on the other hand seem to escape the magnetosphere in an rather narrow range from 1600 LT to 1800 LT. If the dusk magnetopause is the source of CEPs above 150 keV/e, then CEP spectra in that energy range should be especially prominent in the dusk sector of the cusp. In addition, CEP spectra should be harder away from noon. We examine this hypothesis using an exisiting data base of CEP events together with Polar CAMMICE data.
DE: 2720 Energetic particles: trapped
DE: 2724 Magnetopause and boundary layers
DE: 2730 Magnetosphere: inner
DE: 2740 Magnetospheric configuration and dynamics
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005