Solar origin of heliospheric magnetic field inversions: Evidence for coronal loop opening within pseudostreamers

The orientation of the heliospheric magnetic field (HMF) in near‐Earth space is generally a good indicator of the polarity of HMF foot points at the photosphere. There are times, however, when the HMF folds back on itself (is inverted), as indicated by suprathermal electrons locally moving sunward,...

Full description

Saved in:
Bibliographic Details
Published in:Journal of geophysical research. Space physics 2013-05, Vol.118 (5), p.1868-1879
Main Authors: Owens, M. J., Crooker, N. U., Lockwood, M.
Format: Article
Language:English
Subjects:
Corona
coronal magnetic field
heliospheric current sheet
heliospheric magnetic field
interchange reconnection
Magnetic fields
pseudostreamers
slow solar wind
Solar physics
Space exploration
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The orientation of the heliospheric magnetic field (HMF) in near‐Earth space is generally a good indicator of the polarity of HMF foot points at the photosphere. There are times, however, when the HMF folds back on itself (is inverted), as indicated by suprathermal electrons locally moving sunward, even though they must ultimately be carrying the heat flux away from the Sun. Analysis of the near‐Earth solar wind during the period 1998–2011 reveals that inverted HMF is present approximately 5.5% of the time and is generally associated with slow, dense solar wind and relatively weak HMF intensity. Inverted HMF is mapped to the coronal source surface, where a new method is used to estimate coronal structure from the potential‐field source‐surface model. We find a strong association with bipolar streamers containing the heliospheric current sheet, as expected, but also with unipolar or pseudostreamers, which contain no current sheet. Because large‐scale inverted HMF is a widely accepted signature of interchange reconnection at the Sun, this finding provides strong evidence for models of the slow solar wind which involve coronal loop opening by reconnection within pseudostreamer belts as well as the bipolar streamer belt. Occurrence rates of bipolar‐ and pseudostreamers suggest that they are equally likely to result in inverted HMF and, therefore, presumably undergo interchange reconnection at approximately the same rate. Given the different magnetic topologies involved, this suggests the rate of reconnection is set externally, possibly by the differential rotation rate which governs the circulation of open solar flux. Key Points Inverted HMF comprises around 3.5% of the HMF at 1 AUInverted HMF originates at pseudostreamersPseudostreamers contribute coronal loops tot he solar wind
ISSN:2169-9380
2169-9402
DOI:10.1002/jgra.50259