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Title: The role of guide field on magnetic reconnection during island coalescence

A number of studies have considered how the rate of magnetic reconnection scales in large and weakly collisional systems by the modelling of long reconnecting current sheets. However, this set-up neglects both the formation of the current sheet and the coupling between the diffusion region and a larger system that supplies the magnetic flux. Recent studies of magnetic island merging, which naturally include these features, have found that ion kinetic physics is crucial to describe the reconnection rate and global evolution of such systems. In this paper, the effect of a guide field on reconnection during island merging is considered. In contrast to the earlier current sheet studies, we identify a limited range of guide fields for which the reconnection rate, outflow velocity, and pile-up magnetic field increase in magnitude as the guide field increases. The Hall-MHD fluid model is found to reproduce kinetic reconnection rates only for a sufficiently strong guide field, for which ion inertia breaks the frozen-in condition and the outflow becomes Alfvénic in the kinetic system. The merging of large islands occurs on a longer timescale in the zero guide field limit, which may in part be due to a mirror-like instability that occurs upstream ofmore » the reconnection region.« less
Authors:
 [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [1] ;  [2] ;  [3] ;  [3]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Sciberquest, Del Mar, CA (United States)
  3. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Report Number(s):
LA-UR-16-28828
Journal ID: ISSN 1070-664X
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 2; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC). Fusion Energy Sciences (FES) (SC-24); USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1369174
Alternate Identifier(s):
OSTI ID: 1349353

Stanier, Adam John, Daughton, William Scott, Simakov, Andrei Nikolaevich, Chacon, Luis, Le, Ari Yitzchak, Karimabadi, Homa, Ng, Jonathan, and Bhattacharjee, Amitava. The role of guide field on magnetic reconnection during island coalescence. United States: N. p., Web. doi:10.1063/1.4976712.
Stanier, Adam John, Daughton, William Scott, Simakov, Andrei Nikolaevich, Chacon, Luis, Le, Ari Yitzchak, Karimabadi, Homa, Ng, Jonathan, & Bhattacharjee, Amitava. The role of guide field on magnetic reconnection during island coalescence. United States. doi:10.1063/1.4976712.
Stanier, Adam John, Daughton, William Scott, Simakov, Andrei Nikolaevich, Chacon, Luis, Le, Ari Yitzchak, Karimabadi, Homa, Ng, Jonathan, and Bhattacharjee, Amitava. 2017. "The role of guide field on magnetic reconnection during island coalescence". United States. doi:10.1063/1.4976712. https://www.osti.gov/servlets/purl/1369174.
@article{osti_1369174,
title = {The role of guide field on magnetic reconnection during island coalescence},
author = {Stanier, Adam John and Daughton, William Scott and Simakov, Andrei Nikolaevich and Chacon, Luis and Le, Ari Yitzchak and Karimabadi, Homa and Ng, Jonathan and Bhattacharjee, Amitava},
abstractNote = {A number of studies have considered how the rate of magnetic reconnection scales in large and weakly collisional systems by the modelling of long reconnecting current sheets. However, this set-up neglects both the formation of the current sheet and the coupling between the diffusion region and a larger system that supplies the magnetic flux. Recent studies of magnetic island merging, which naturally include these features, have found that ion kinetic physics is crucial to describe the reconnection rate and global evolution of such systems. In this paper, the effect of a guide field on reconnection during island merging is considered. In contrast to the earlier current sheet studies, we identify a limited range of guide fields for which the reconnection rate, outflow velocity, and pile-up magnetic field increase in magnitude as the guide field increases. The Hall-MHD fluid model is found to reproduce kinetic reconnection rates only for a sufficiently strong guide field, for which ion inertia breaks the frozen-in condition and the outflow becomes Alfvénic in the kinetic system. The merging of large islands occurs on a longer timescale in the zero guide field limit, which may in part be due to a mirror-like instability that occurs upstream of the reconnection region.},
doi = {10.1063/1.4976712},
journal = {Physics of Plasmas},
number = 2,
volume = 24,
place = {United States},
year = {2017},
month = {2}
}