HR: 0830h
AN: SM41A-01    [Abstracts]
TI: Angular Distribution of Neutral Atoms in the Solar Wind on October 24 & 31, 2003
AU: * Vieira, G B
AF: Department of Physics, University of Maryland, College Park, MD 20742-4111 United States
AU: Hill, M E
EM: mehill@umd.edu
AF: Department of Physics, University of Maryland, College Park, MD 20742-4111 United States
AU: Hamilton, D C
AF: Department of Physics, University of Maryland, College Park, MD 20742-4111 United States
AU: Fok, M -
AF: NASA, Goddard Spaceflight Center, Greenbelt, MD 20771 United States
AU: Collier, M R
AF: NASA, Goddard Spaceflight Center, Greenbelt, MD 20771 United States
AU: Moore, T E
AF: NASA, Goddard Spaceflight Center, Greenbelt, MD 20771 United States
AU: Mitchell, D G
AF: Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 United States
AU: Skoug, R M
AF: Los Alamos National Laboratory, LANL, Los Alamos, NM 87545 United States
AU: Desai, M I
AF: Department of Physics, University of Maryland, College Park, MD 20742-4111 United States
AB: In 2003, during intervals of magnetospheric compression on October 24 and 31, the IMAGE spacecraft was in the solar wind, upstream of the Earth's bow shock. While in the solar wind, the Low Energy Neutral Atom (LENA) instrument detected an unusually wide and intense angular distribution of energetic neutral hydrogen centered about the solar direction. These measurements resemble LENA's repeated observation of a narrower, less intense energetic neutral atom (ENA) distribution, thought to result from charge exchange interactions between magnetosheath ions and geocoronal hydrogen. The uniqueness of these excursions into the solar wind results from the changing IMAGE orbit; the line of apsides of the precessing orbit was only briefly near the Sun-Earth line, with an apogee of 8 R_E toward the Sun, the most favorable orientation for entry into the solar wind. We investigate the ion populations present during the 2003 events, including those detected at IMAGE by the HENA instrument and upstream at ACE with the SWEPAM and ULEIS instruments. We consider solar wind and suprathermal ions that charge exchange with geocoronal hydrogen as potential ENA sources and model the resultant ENA distribution. We will report on the likely source of these ENAs in the solar wind, with particular attention to understanding their angular distribution.
DE: 2151 Neutral particles
DE: 2164 Solar wind plasma
DE: 2728 Magnetosheath
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2005 Joint Assembly