Anomalous magnetosheath flows and distorted subsolar magnetopause for radial interplanetary magnetic fields

• Published in: Geophysical research letters Vol. 36; no. 18; pp. L18112 - n/a
• Main Authors: Shue, J.-H., Chao, J.-K., Song, P., McFadden, J. P., Suvorova, A., Angelopoulos, V., Glassmeier, K. H., Plaschke, F.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01.09.2009; Blackwell Publishing Ltd; John Wiley & Sons, Inc
• Subjects: Atmospheric sciences; Discontinuity; Distortion; Earth sciences; Earth, ocean, space; Exact sciences and technology; Flow; Indentation; Interplanetary magnetic fields; Magnetic fields; Magnetism; Magnetopause; Magnetopause and boundary layers; Magnetosheath; Magnetosphere; Magnetospheric Physics; Mathematical analysis; outer; solar wind; Solar wind/magnetosphere interactions; Vectors (mathematics); magnetosheath; magnetopause; solar wind; Interplanetary magnetic field; tangential discontinuities; Magnetosheath; Magnetopause; Slow flow; Indentation; direction
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2009GL039842

On 12 August 2007 from 1436 to 1441 UT, when the five THEMIS probes (THA, THB, THC, THD, and THE) were located near the subsolar magnetopause, a sunward flow was observed in the magnetosheath. A fast anti‐sunward flow (−280 km/s) was observed in the magnetosheath before the sunward flow. Although THA observed this fast anti‐sunward flow, THC and THD, which were also in the magnetosheath, instead observed a slow flow, indicating that the fast flow was small in scale. With the observed flow vectors and the magnetopause normal directions estimated from tangential discontinuity analysis, we conclude that this fast flow creates an indentation on the magnetopause, 1 RE deep and 2 RE wide. The magnetopause subsequently rebounds, rotating the flow direction sunward along the surface of the magnetopause. The fast flow is likely related to the radial interplanetary magnetic field.