An MMS Multicase Study of Magnetotail Dipolarization Fronts

Schmid, Daniel

An MMS Multicase Study of Magnetotail Dipolarization Fronts

Thursday, October 1, 2015

Daniel Schmid^1,2, Rumi Nakamura¹, Ferdinand Plaschke¹, Martin Volwerk¹, Wolfgang Baumjohann¹, Werner Magnes¹, David Fischer¹, Roy B Torbert^3,4, C. T. Russell⁵, Robert J Strangeway⁶, Hannes Karl Leinweber⁵, Kenneth R Bromund⁷, Brian J Anderson⁸, Mark Chutter³, James A Slavin⁹, Larry Kepko⁷, Mark Moldwin⁹ and Olivier Le Contel¹⁰, (1)Space Research Institute, Austrian Academy of Sciences, Graz, Austria, (2)University of Graz, NAWI, Graz, Austria, (3)University of New Hampshire, Durham, NH, United States, (4)Southwest Research Institute San Antonio, San Antonio, TX, United States, (5)University of California Los Angeles, Los Angeles, CA, United States, (6)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States, (7)NASA/GSFC, Greenbelt, MD, United States, (8)Johns Hopkins Univ Applied Phy, Laurel, MD, United States, (9)University of Michigan, Ann Arbor, MI, United States, (10)Laboratoire de Physique des Plasmas, Paris, France

Abstract:

Dipolarization fronts (DFs) are characterized by a rapid increase in the northward magnetic field component (Bz) and play a crucial role in the energy and magnetic flux transport in the magnetotail. Multispacecraft observations of DFs in a large portion of the magnetotail by e.g. Geotail, Cluster and THEMIS have been reported for over three decades.

During the commissioning phase of MMS we are able to observe DFs at radial distances within 8 Re, which is in a more dipolarized region (well within the flow braking region).
We present a statistical study of DFs observed during March-May 2015, using only magnetic field data. First results indicate that the amplitude of the found DFs is greater compared to similar events in the distant tail. Timing analysis yields that many of the DFs propagate tailward, which would suggest a rebound (bouncing) of the DF at the magnetic dipole-dominated near-Earth plasma sheet. Since MMS spacecraft are in a “string-of-pearls” configuration, further analysis is ongoing to evaluate the obtained direction from a simple timing analysis.
We compare and contrast the found DFs with that from the DF-eventlist introduced in Schmid et al. [J. Geophys. Res., 2, 120 (2015)], which is based on 9 years (2001-2009) of Cluster magnetotail observations.