Title: Scaling the Ion Inertial Length and Its Implications for Modeling Reconnection in Global Simulations

Abstract

Abstract We investigate the use of artificially increased ion and electron kinetic scales in global plasma simulations. We argue that as long as the global and ion inertial scales remain well separated, (1) the overall global solution is not strongly sensitive to the value of the ion inertial scale, while (2) the ion inertial scale dynamics will also be similar to the original system, but it occurs at a larger spatial scale, and (3) structures at intermediate scales, such as magnetic islands, grow in a self‐similar manner. To investigate the validity and limitations of our scaling hypotheses, we carry out many simulations of a two‐dimensional magnetosphere with the magnetohydrodynamics with embedded particle‐in‐cell (MHD‐EPIC) model. The PIC model covers the dayside reconnection site. The simulation results confirm that the hypotheses are true as long as the increased ion inertial length remains less than about 5% of the magnetopause standoff distance. Since the theoretical arguments are general, we expect these results to carry over to three dimensions. The computational cost is reduced by the third and fourth powers of the scaling factor in two‐ and three‐dimensional simulations, respectively, which can be many orders of magnitude. The present results suggest that global simulationsmore » that resolve kinetic scales for reconnection are feasible. This is a crucial step for applications to the magnetospheres of Earth, Saturn, and Jupiter and to the solar corona.« less

Authors:

Tóth, Gábor  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5654-9823"

Chen, Yuxi ^[1]; Gombosi, Tamas I. ^[1]; Cassak, Paul  ^[2];

• Search DOE PAGES for author "Cassak, Paul"
• Search DOE PAGES for ORCID "0000-0002-5938-1050"

Markidis, Stefano ^[3]; Peng, Ivy Bo ^[3]

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+ Show Author Affiliations

1. Center for Space Environment Modeling University of Michigan Ann Arbor MI USA
2. Department of Physics and Astronomy West Virginia University Morgantown WV USA
3. Department for Computational Science and Technology KTH Royal Institute of Technology Stockholm Sweden

Publication Date:

Sat Oct 21 00:00:00 EDT 2017

Sponsoring Org.:

USDOE

OSTI Identifier:

1402087

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Space Physics

Additional Journal Information:

Journal Name: Journal of Geophysical Research. Space Physics Journal Volume: 122 Journal Issue: 10; Journal ID: ISSN 2169-9380

Publisher:

American Geophysical Union (AGU)

Country of Publication:

United States

Language:

English