Global and local properties of dayside magnetopause reconnection: Simulations and initial MMS results

Dorelli, John

Global and local properties of dayside magnetopause reconnection: Simulations and initial MMS results

Thursday, October 1, 2015

John Dorelli¹, Daniel J Gershman², Alex Glocer¹, Colin M Komar³, Levon A Avanov¹, William S Daughton⁴, Li-Jen Chen⁵, Roy B Torbert⁶, Craig J Pollock¹, Gabor Toth⁷, Ulrik Gliese¹, Alexander Barrie⁸, Chad Salo⁹, Charles Dickson¹⁰, Matthew P Holland¹, Barbara L Giles¹, Christopher T Russell¹¹, Wolfgang Baumjohann¹², Victoria N Coffey¹³, Elizabeth MacDonald¹ and Yoshifumi Saito¹⁴, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)NASA/GSFC, Greenbelt, MD, United States, (3)West Virginia University, Morgantown, WV, United States, (4)MS-F699, Plasma Theory and App, Los Alamos, NM, United States, (5)Univ of New Hampshire, Durham, NH, United States, (6)Univ New Hampshire, Durham, NH, United States, (7)University of Michigan, Ann Arbor, MI, United States, (8)Millenium Engineering and Integration Company, Arlington, VA, United States, (9)Stellar Solutions, Palo Alto, CA, United States, (10)AS and D, Inc., Beltsville, MD, United States, (11)University of California Los Angeles, Los Angeles, CA, United States, (12)Austrian Academy of Sciences, Graz, Austria, (13)NASA Marshall Space Flight Center, Huntsville, AL, United States, (14)ISAS Institute of Space and Astronautical Science, Kanagawa, Japan

Abstract:

Recent high resolution global magnetohydrodynamics (MHD) simulations of Earth's magnetosphere [Komar et al., 2013, Glocer et al., 2015] suggest that dayside magnetopause reconnection occurs at topological separators that extend across the entire dayside -- stretching from one polar cusp to the other -- for both northward and southward Interplanetary Magnetic Field (IMF) conditions. The recent simulations, performed using the BATS-R-US code, confirm previous results for generic northward IMF conditions obtained using the OpenGGCM code [Dorelli et al., 2007]: The simulated magnetosphere has a global magnetic topology consistent with that of a vacuum superposition (in which a uniform IMF is superposed on a dipole), predicting that component subsolar reconnection is topologically possible for essentially all IMF clock angles (excluding the singular pure northward case). Recent PIC simulations using the massively parallel VPIC code [Daughton et al., 2014], however, suggest that secondary island formation at the magnetopause produces turbulence and field line chaos, making the identification of topological X lines difficult or impossible (indeed, Daughton et al. [2014] suggest that the concept of "X line" loses its relevance in such turbulent reconnection scenarios). In this work, we present new high resolution BATS-R-US (both resistive and Hall MHD) and VPIC simulations demonstrating that topological separators exist in non-toroidal topologies (like the dayside magnetopause) even in the presence of secondary magnetic islands and associated turbulence. We use a high fidelity model of the Fast Plasma Investigation (FPI) on the Magnetospheric Multiscale (MMS) mission to predict local plasma signatures that can be used to identify topological separators, and we compare our simulations with initial observations from the FPI and FIELDS suites on MMS.

Komar et al., JGR, 2013.

Glocer et al., JGR, 2015 (submitted).

Dorelli et al., JGR, 2007.

Daughton et al., Phys. Plasmas, 2014.