Characterizing the Alfvénic slow wind: A case study
Date Issued
2016
Author(s)
Abstract
Alfvénicity is a feature characterizing solar wind fluctuations and is defined by a high correlation between velocity and magnetic field components and in ideal conditions by equipartition between kinetic and magnetic energies. It is a feature characterizing especially the fast wind while slow wind shows usually lower correlation between velocity and magnetic field components. However this is not always the case. Under certain conditions a high degree of Alfvénicity can be found also within slow wind. In the present paper, we show the existence of two kinds of slow solar wind with similar velocities but which display different characteristics. The different degree of Alfvénicity is a feature discrimanating the two types of slow wind. This feature is always linked to a low magnetic field compressibility as shown in the present paper using a case study. It is found that the Alfvénic slow wind is more similar to fast wind rather than to the standard slow wind apart from velocity. This fact can be attributed to a different source region on the solar surface. Actually the standard slow wind comes from coronal streamers or active regions while the Alfvénic slow wind originates from the boundary of coronal holes sharing characteristics typical of fast wind.
Coverage
SOLAR WIND 14: Proceedings of the Fourteenth International Solar Wind Conference
All editors
Wang, Linghua; Bruno, Roberto; Möbius, Eberhard; Vourlidas, Angelos; Zank, Gary
Series
Volume
1720
Issue
1
Start page
040002-1
Conferenece
SOLAR WIND 14: Fourteenth International Solar Wind Conference
Conferenece place
Weihai, China
Conferenece date
22-25 June, 2015
Issn Identifier
0094-243X
Ads BibCode
2016AIPC.1720d0002D
Rights
open.access
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