HR: 0800h
AN: SH21A-0293    [Abstracts]
TI: Strahl properties in the solar wind: Observations
AU: Stverak, S
EM: stepan.stverak@centrum.cz
AF: Institute of Atmospheric Physics, AS CR, Bocni II, 1401, Prague, 14131, Czech Republic
AU: Stverak, S
EM: stepan.stverak@centrum.cz
AF: LESIA, Observatoire de Paris, CNRS, 5 place Julese Janssen, Meudon, 92195, France
AU: * Maksimovic, M
EM: milan.maksimovic@obspm.fr
AF: LESIA, Observatoire de Paris, CNRS, 5 place Julese Janssen, Meudon, 92195, France
AU: Travnicek, P
EM: trav@alenka.ufa.cas.cz
AF: Institute of Atmospheric Physics, AS CR, Bocni II, 1401, Prague, 14131, Czech Republic
AU: Travnicek, P
EM: trav@alenka.ufa.cas.cz
AF: Astronomical Institute, AS CR, Bocni II, 1401, Prague, 14131, Czech Republic
AU: Marsch, E
EM: marsch@linmpi.mpg.de
AF: Max Planck Institute for Solar System Research, Max-Planck-Strasse 2, Katlenburg-Lindau, 37191, Germany
AU: Fazakerley, A N
EM: anf@mssl.ucl.ac.uk
AF: Mullard Space Science Lab., Holmbury St. Mary, Dorking, RH5 6NT, United Kingdom
AU: Scime, E E
EM: escime@wvu.edu
AF: Department of Physics, West Virginia University, 209 Hodges Hall, Morgantown, 26506- 6315, United States
AB: We have performed a statistical study of a substantial amount of electron data acquired in the solar wind to describe the properties of the strahl electron population. We use a large data set of electron measurements from three different spacecraft (HELIOS I, CLUSTER II and ULYSSES) collected in the low ecliptic latitudes covering the radial distance from the Sun from 0.3 up to 4 AU. Beside the thermal core, the electron velocity distribution functions in the solar wind typically exhibit two non-thermal features: supra thermal tails known as the halo population and the strahl. This last component is highly aligned in the direction parallel to the interplanetary magnetic field and is largely moving away from the Sun. Even thought it comprises less than a few percents of the total number density, it is important to study some important solar wind plasma properties. Thanks its attributes, the strahl is responsible for the main part of the electron heat flux and it can also provide a possible source of electron kinetic plasma instabilities. We fit the observed distribution functions with analytical models. The resulting characteristics are compared with other electron properties in order to study their possible correlations. In addition we examine the radial evolution of these characteristics during the expansion of the solar wind.
DE: 2164 Solar wind plasma
DE: 7800 SPACE PLASMA PHYSICS
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting