An indication of the existence of a solar wind strahl at 10AU

Walsh, A. P. and Arridge, C. S. and Masters, A. and Lewis, Gethyn. R. and Fazakerley, A. N. and Jones, Geraint. H. and Owen, C. J. and Coates, A. J. (2013) An indication of the existence of a solar wind strahl at 10AU. Geophysical Research Letters, 40 (11). pp. 2495-2499. ISSN 0094-8276

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Abstract

The solar wind electron distribution is observed near and within 1AU to consist of three components: a thermal core, a suprathermal halo, and a suprathermal strahl. The former two components are isotropic, while the strahl is field aligned and flows outward along the interplanetary magnetic field. The evolution of solar wind electrons with heliocentric distance is poorly understood; although the halo is thought to be formed through pitch angle (PA) scattering of the strahl, the responsible physical process has not been conclusively identified. Measurements of solar wind electrons throughout the heliosphere are required to solve this problem. We present the first observations of the suprathermal components of the solar wind electron distribution made outside 5AU. We find indications of a strahl component narrower than that predicted by extrapolating observations and models of electrons in the inner heliosphere, suggesting the rate of electron pitch angle scattering in the solar wind can decrease with increasing heliocentric distance.

Item Type:
Journal Article
Journal or Publication Title:
Geophysical Research Letters
Additional Information:
©2013. American Geophysical Union
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900
Subjects:
ID Code:
74030
Deposited By:
Deposited On:
18 Jun 2015 05:59
Refereed?:
Yes
Published?:
Published
Last Modified:
07 Jul 2020 03:51