skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas

Abstract

This paper reviews the progress in understanding the fundamental physics of magnetic reconnection, focusing on significant results in the past decade from dedicated laboratory experiments, numerical simulations, and space astrophysical observations. Particularly in the area of local reconnection physics, many important findings have been made with respect to two-fluid dynamics, the profile of the neutral sheet, the effects of guide field, and scaling laws with respect to collisionality. Notable findings have been made on global reconnection dynamics through detailed documentation of magnetic self-organization phenomena in fusion plasmas as well as in solar flares. After a brief review of the well-known early work, we will discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. Especially, the recent data on local reconnection physics from the Magnetic Reconnection Experiment device [M. Yamada et al., Phys. Plasmas 13, 052119 (2006)] are used to compare experimental and numerical results.

Authors:
 [1]
  1. Center of Magnetic Self-organization in Laboratory and Astrophysical Plasmas, Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543-0451 (United States)
Publication Date:
OSTI Identifier:
20975094
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2740595; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; COLLISIONS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; FOCUSING; MAGNETIC RECONNECTION; MAGNETOHYDRODYNAMICS; PLASMA; SCALING LAWS; SOLAR FLARES; SPACE

Citation Formats

Yamada, Masaaki. Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas. United States: N. p., 2007. Web. doi:10.1063/1.2740595.
Yamada, Masaaki. Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas. United States. doi:10.1063/1.2740595.
Yamada, Masaaki. Tue . "Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas". United States. doi:10.1063/1.2740595.
@article{osti_20975094,
title = {Progress in understanding magnetic reconnection in laboratory and space astrophysical plasmas},
author = {Yamada, Masaaki},
abstractNote = {This paper reviews the progress in understanding the fundamental physics of magnetic reconnection, focusing on significant results in the past decade from dedicated laboratory experiments, numerical simulations, and space astrophysical observations. Particularly in the area of local reconnection physics, many important findings have been made with respect to two-fluid dynamics, the profile of the neutral sheet, the effects of guide field, and scaling laws with respect to collisionality. Notable findings have been made on global reconnection dynamics through detailed documentation of magnetic self-organization phenomena in fusion plasmas as well as in solar flares. After a brief review of the well-known early work, we will discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. Especially, the recent data on local reconnection physics from the Magnetic Reconnection Experiment device [M. Yamada et al., Phys. Plasmas 13, 052119 (2006)] are used to compare experimental and numerical results.},
doi = {10.1063/1.2740595},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • This paper reviews the progress in understanding the fundamental physics of magnetic reconnection, focusing on significant results in the past decade from dedicated laboratory experiments, numerical simulations, and space astrophysical observations. Particularly in the area of local reconnection physics, many important findings have been made with respect to two-fluid dynamics, the profile of the neutral sheet, the effects of guide field, and scaling laws with respect to collisionality. Notable findings have been made on global reconnection dynamics through detailed documentation of magnetic self-organization phenomena in fusion plasmas as well as in solar flares. After a brief review of the well-knownmore » early work, we will discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. Especially, the recent data on local reconnection physics from the Magnetic Reconnection Experiment device [M. Yamada et al., Phys. Plasmas 13, 052119 (2006)] are used to compare experimental and numerical results.« less
  • Maxwell's equations imply that exponentially smaller non-ideal effects than commonly assumed can give rapid magnetic reconnection in space and astrophysical plasmas. In an ideal evolution, magnetic field lines act as stretchable strings, which can become ever more entangled but cannot be cut. High entanglement makes the lines exponentially sensitive to small non-ideal changes in the magnetic field. The cause is well known in popular culture as the butterfly effect and in the theory of deterministic dynamical systems as a sensitive dependence on initial conditions, but the importance to magnetic reconnection is not generally recognized. Two-coordinate models are too constrained geometricallymore » for the required entanglement, but otherwise the effect is general and can be studied in simple models. A simple model is introduced, which is periodic in the x and y Cartesian coordinates and bounded by perfectly conducting planes in z. Starting from a constant magnetic field in the z direction, reconnection is driven by a spatially smooth, bounded force. The model is complete and could be used to study the impulsive transfer of energy between the magnetic field and the ions and electrons using a kinetic plasma model.« less
  • Recent progress in understanding the physics of magnetic reconnection is conveniently summarized in terms of a phase diagram which organizes the essential dynamics for a wide variety of applications in heliophysics, laboratory, and astrophysics. The two key dimensionless parameters are the Lundquist number and the macrosopic system size in units of the ion sound gyroradius. In addition to the conventional single X-line collisional and collisionless phases, multiple X-line reconnection phases arise due to the presence of the plasmoid instability either in collisional and collisionless current sheets. In particular, there exists a unique phase termed ''multiple X-line hybrid phase'' where amore » hierarchy of collisional islands or plasmoids is terminated by a collisionless current sheet, resulting in a rapid coupling between the macroscopic and kinetic scales and a mixture of collisional and collisionless dynamics. The new phases involving multiple X-lines and collisionless physics may be important for the emerging applications of magnetic reconnection to accelerate charged particles beyond their thermal speeds. A large number of heliophysical and astrophysical plasmas are surveyed and grouped in the phase diagram: Earth's magnetosphere, solar plasmas (chromosphere, corona, wind, and tachocline), galactic plasmas (molecular clouds, interstellar media, accretion disks and their coronae, Crab nebula, Sgr A*, gamma ray bursts, and magnetars), and extragalactic plasmas (active galactic nuclei disks and their coronae, galaxy clusters, radio lobes, and extragalactic jets). Significance of laboratory experiments, including a next generation reconnection experiment, is also discussed.« less