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Session 34 - Solar System.
Display session, Tuesday, June 11
Tripp Commons,

[34.01] EUVE Detection of the Local Interstellar Wind via Resonance Scattering of Solar He I 584 Å

B. Flynn, J. Vallerga (CEA/UCB), F. Dalaudier (CNRS), G. R. Gladstone (SwRI)

We present initial results from EUVE\/ measurements of interplanetary and geocoronal He I 584 Å\ emission made during the all-sky survey. The data consist of count rates from the tin quadrants (520--750 Åof Scanner C obtained over a 1 year period from July 1992 to July 1993. During this period, EUVE\/ was in survey mode so that the scanners made 360^\circ sweeps of the sky in a plane perpendicular to the Sun-Earth line. The interplanetary He I signal is morphologically consistent with previous observations, such as Prognoz 6\/ (Dalaudier et al.\ 1984, Aamp;A, v134). However, unlike the Prognoz 6\/ data, the EUVE\/ measurements were made from low Earth orbit (512 km) and so contain geocoronal emission as well. As a result, along sight lines where the relative speed between the interplanetary wind and the Earth is at a minimum, absorption of the interplanetary signal by the geocorona occurs. We anticipate model fits to our data to yield: interplanetary He parameters; (2) solar He I Ly\alpha line information; and (3) geocoronal He column abundance and temperature. This work is supported by NASA contract NAS5-29298.

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