Orientation of solar wind dynamic pressure phase fronts. Issue 4 (16th April 2013)

• Record Type: Journal Article
• Authors: Jackel, Brian J.; Cameron, Taylor; Weygand, James M.
• Is Part Of: Journal of geophysical research. Volume 118:Issue 4(2013:Apr.)
• Page Start: 1379
• Page End: 1388
• Publication Date: 2013-04-16
• Subjects: solar wind -- dynamic pressure -- magnetic field; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/jgra.50183
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract : [1] Orientation of structures in the solar wind plays an important role when attempting to use upstream observations at L1 for prediction of subsequent conditions near the Earth. In this study, the relationship between solar wind dynamic pressure forcing and geosynchronous magnetic field response is used to determine a very large set of lagged correlations between the ACE and GOES satellites. Effects due to tilted solar wind structures are explored using the dispersion of arrival times relative to a simple phase plane model. Assuming that structure phase‐front normal vectors were located in the GSE‐ xy plane, we found a characteristic azimuth of 15°. Similar analysis carried out with velocity scaling according to the Parker spiral model did not produce an improved fit. Binning by average interplanetary magnetic field (IMF) B → orientation produced a clear pattern in characteristic azimuth, with phase‐front normals perpendicular to both the predominant Parker spiral orientation and the less common ortho‐spiral configuration. An empirical relationship φ n ̂ = − 4 5 ° sin ( 2 φ B ) was found to predict phase‐front normal azimuth over the entire range of observed IMF azimuths. The effects of lateral displacement from the Sun‐Earth line in the GSE‐ z direction are comparable to those for GSE‐ y, indicating that solar wind structures are often significantly inclined with respect to the ecliptic plane. Key Points: Solar wind dynamic pressure and geosynchronous magnetic field correlation Phase front normals perpendicular to Parker spiral and orthospiral Effect of GSE‐Y, Z comparable so structures often significantly inclined