HR: 0830h
AN: SA21A-06    [Abstracts]
TI: Particle albedo in proton aurora
AU: * Galand, M
EM: mgaland@bu.edu
AF: Center for Space Physics / Boston University, 725 Commonwealth Ave, Boston, MA 02215 United States
AU: Chakrabarti, S
EM: supc@bu.edu
AF: Center for Space Physics / Boston University, 725 Commonwealth Ave, Boston, MA 02215 United States
AU: Peticolas, L M
EM: lmp@ssl.berkeley.edu
AF: Space Sciences Lab / University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450 United States
AU: Carlson, C W
EM: cwc@ssl.berkeley.edu
AF: Space Sciences Lab / University of California, Berkeley, 7 Gauss Way, Berkeley, CA 94720-7450 United States
AB: A unique signature of proton precipitation in the auroral regions is the Doppler-shifted H emissions. These emissions have been widely observed from ground and space as a tracer of magnetospheric regions and processes and as a probe of particle energy input upon the high latitude regions. Spectroscopic observations of H emissions are required for any quantitative assessment of the incident proton flux. Without information on the spectral profile of the H emission, any quantitative analysis is limited by strong assumptions on the hardness of the precipitation. A spectral resolution of 0.2 nm or less over a spectral range of at least 8 nm is required for a suitable analysis of the H Balmer emissions. A particular feature of the spectral profile of H emissions is the presence of a red-shifted wing (for field-aligned viewing from the ground). Such a feature is induced by upgoing H atoms produced within the proton beam. Few proton/H atom transport comprehensive models include angular redistribution processes and to date no direct validation of the upward particle flux in proton aurora has been performed. The NASA FAST mission offers the unique opportunity to provide measurements of downward and upward proton fluxes at a high angular resolution at the top of the atmosphere. We have recently improved our proton transport model for a more detailed evaluation of the upward fluxes including an energy-dependent phase function for collisional angular redistribution. We will validate this new model using particle fluxes observed by the FAST satellite.
DE: 2407 Auroral ionosphere (2704)
DE: 2447 Modeling and forecasting
DE: 2455 Particle precipitation
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly