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Electron Velocity Distribution Function in Magnetic Clouds in the Solar WindWe present a study of the kinetic properties of the electron velocity distribution functions within magnetic clouds, since they are the dominant thermal component. The study is based on high time resolution data from the GSFC WIND/SWE electron spectrometer and the Berkeley 3DP electron plasma instruments. Recent studies on magnetic clouds have shown observational evidence of anti-correlation between the total electron density and electron temperature, which suggest a polytrope law P(sub e) = alpha(Nu(sub e) (sup gamma)) for electrons with the constant gamma approximates 0.5 < 1. This anti-correlation and small polytropic gamma-values is interpreted in the context of the presence of highly non-Maxwellian electron distributions (i.e. non-thermal) within magnetic clouds. These works suggested that the non-thermal electrons can contribute as much as 50% of the total electron pressure within magnetic clouds. We have revisited some of the magnetic cloud events previously studied and attempted to quantify the nature of the non-thermal electrons by modeling the electron velocity distribution function using a kappa distribution function to characterize the kinetic non-thermal effects. If non-thermal tail effects are the source for the anti-correlation between the moment electron temperature and density and if the kappa distribution is a reasonable representative model of non-thermal effects, then the electron velocity distribution within magnetic clouds should show indication for small K-values when gamma < 1.
Document ID
20070032730
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Nieves-Chinchil, Teresa
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Vinas, Adolfo F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Bale, Stuart D.
(California Univ. Berkeley, CA, United States)
Date Acquired
August 23, 2013
Publication Date
December 11, 2006
Publication Information
Publisher: American Geophysical Union
Subject Category
Solar Physics
Report/Patent Number
AGU-10208381
Meeting Information
Meeting: American Geophysical Union Fall 2006 Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 11, 2006
End Date: December 15, 2006
Distribution Limits
Public
Copyright
Other

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