[IGPP Everyone] SPACE SCIENCE SEMINAR - WINTERQUARTER -Geology 6704- 3:30pm -Friday March 13, 2020

[Marjorie Sowmendran]

SPACE PHYSICS SEMINAR

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES

UNIVERSITY OF CALIFORNIA, LOS ANGELES

(AOS M275B, EPSS M288B)







Magnetic Curvature Force and the Physics of Current Sheets in the Magnetosheath

R. J. Strangeway

EPSS,  UCLA



Abstract: The Magnetospheric Multiscale mission (MMS), consisting of four closely spaced Earth-orbiting spacecraft, has provided unprecedented high quality and high temporal resolution data that has provided new insights into the process of reconnection at both the dayside magnetopause and the nightside current sheet. MMS has also shown that the magnetosheath itself can be highly structured. Several research groups have reported on strong current sheets observed within the magnetosheath itself that appear to be separate from the magnetopause current. Various hypotheses have been forwarded to explain these structures, including fast plasma jets from the bow shock, interacting flux ropes/flux transfer events (FTEs), and dusty plasma interactions. In order to elucidate the causes for these current sheets we analyze the force associated with magnetic field-line curvature and we find that the curvature force can offset the excess pressure force often observed at or near the current sheet. This suggests that the interacting flux-rope/FTE hypothesis best explains the events, but this leads to further questions. Specifically, the magnetic field signatures suggest that if the source is due to flux-rope/FTE entanglement then the current sheets are highly evolved. In addition, while the current is mainly field-aligned, it is not clear how this current closes as the entangled structures become un-entangled.

                                                                                                          Friday March 13, 2020

Room 6704 Geology

3:30 - 5:00 PM

In-charge: C. T. Russell 

                    


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