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Properties of the solar wind electrons between 1 and 3.3 AU from Ulysses thermal noise measurementsIn order to describe the distribution function f(v) of the solar wind electrons, the simplest model which is commonly used consists of the sum of two Maxwellians representing two distinct populations: a core (density n(sub c), temperature T(sub c)) and a halo (density n(sub h), temperature T(sub h)). It is possible, with the latter assumptions on the electron f(v), to determine the quasi-thermal noise (QTN) induced on an antenna by the motion of the ambient electrons in the solar wind. Using this distribution and the spectroscopy of thermal noise measurements from the radio receiver on Ulysses in the ecliptic plane, we deduce the total electron density N(sub e), the core temperature T(sub c), and the core and halo kinetic pressures N(sub c)T(sub c) and N(sub h)T(sub h). From these electron parameters, we can define a 'global' electron temperature as T(sub e) = (N(sub c)T(sub c) + N(sub h)T(sub h))/N(sub e). Here we present different radial gradients of T(sub e), between 1 and 3.3 AU, as a function of three classes of N(sub e) at 1 AU: low, intermediate, and high densities. In general all these gradients are found to be positive with different polytrope power law indexes between N(sub e) and T(sub e), which are in general lower than unity. We also show different behaviors of the ratio N(sub h)T(sub h)/N(sub c)T(sub c) for each density class considered. Some possible interpretations for these observations are discussed.
Document ID
19960021397
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Maksimovic, M.
(Observatoire de Paris-Meudon France)
Hoang, S.
(Observatoire de Paris-Meudon France)
Bougeret, J. L.
(Observatoire de Paris-Meudon France)
Date Acquired
August 17, 2013
Publication Date
June 30, 1995
Publication Information
Publication: International Solar Wind 8 Conference
Subject Category
Solar Physics
Accession Number
96N24793
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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