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Title: Magneto-thermal reconnection processes, related mode momentum and formation of high energy particle populations

In the context of a two-fluid theory of magnetic reconnection, when the longitudinal electron thermal conductivity is relatively large, the perturbed electron temperature tends to become singular in the presence of a reconnected field component and an electron temperature gradient. A finite transverse thermal diffusivity removes this singularity while a finite ‘inductivity’ can remove the singularity of the relevant plasma displacement. Then (i) a new ‘magneto-thermal’ reconnection producing mode, is found with characteristic widths of the reconnection layer remaining significant even when the macroscopic distances involved are very large; (ii) the mode phase velocities can be both in the direction of the electron diamagnetic velocity as well in the opposite (ion) direction. A numerical solution of the complete set of equations has been carried out with a simplified analytical reformulation of the problem. A sequence of processes is analyzed to point out that high-energy particle populations can be produced as a result of reconnection events. These processes involve mode-particle resonances transferring energy of the reconnecting mode to a superthermal ion population and the excitation of lower hybrid waves that can lead to a significant superthermal electron population. The same modes excited in axisymmetric (e.g. toroidal) confinement configurations can extract angularmore » momentum from the main body of the plasma column and thereby sustain a local ‘spontaneous rotation’ of it.« less
Authors:
 [1] ;  [1] ;  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Boston Univ., MA (United States)
Publication Date:
Grant/Contract Number:
FG02-03ER54700
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 7; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; magneto-thermal reconnection; electron temperature gradient; high energy particle populations
OSTI Identifier:
1429496

Coppi, B., Basu, B., and Fletcher, A.. Magneto-thermal reconnection processes, related mode momentum and formation of high energy particle populations. United States: N. p., Web. doi:10.1088/1741-4326/aa6c70.
Coppi, B., Basu, B., & Fletcher, A.. Magneto-thermal reconnection processes, related mode momentum and formation of high energy particle populations. United States. doi:10.1088/1741-4326/aa6c70.
Coppi, B., Basu, B., and Fletcher, A.. 2017. "Magneto-thermal reconnection processes, related mode momentum and formation of high energy particle populations". United States. doi:10.1088/1741-4326/aa6c70. https://www.osti.gov/servlets/purl/1429496.
@article{osti_1429496,
title = {Magneto-thermal reconnection processes, related mode momentum and formation of high energy particle populations},
author = {Coppi, B. and Basu, B. and Fletcher, A.},
abstractNote = {In the context of a two-fluid theory of magnetic reconnection, when the longitudinal electron thermal conductivity is relatively large, the perturbed electron temperature tends to become singular in the presence of a reconnected field component and an electron temperature gradient. A finite transverse thermal diffusivity removes this singularity while a finite ‘inductivity’ can remove the singularity of the relevant plasma displacement. Then (i) a new ‘magneto-thermal’ reconnection producing mode, is found with characteristic widths of the reconnection layer remaining significant even when the macroscopic distances involved are very large; (ii) the mode phase velocities can be both in the direction of the electron diamagnetic velocity as well in the opposite (ion) direction. A numerical solution of the complete set of equations has been carried out with a simplified analytical reformulation of the problem. A sequence of processes is analyzed to point out that high-energy particle populations can be produced as a result of reconnection events. These processes involve mode-particle resonances transferring energy of the reconnecting mode to a superthermal ion population and the excitation of lower hybrid waves that can lead to a significant superthermal electron population. The same modes excited in axisymmetric (e.g. toroidal) confinement configurations can extract angular momentum from the main body of the plasma column and thereby sustain a local ‘spontaneous rotation’ of it.},
doi = {10.1088/1741-4326/aa6c70},
journal = {Nuclear Fusion},
number = 7,
volume = 57,
place = {United States},
year = {2017},
month = {5}
}