Measurements of magnetic fluctuations in magnetic reconnection experiment

H. Ji, M. Yamada, S. Terry, R. Kulsrud, Y. Ren, A. Kuritsyn

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Magnetic reconnection plays an important role in determining the evolution of magnetic topology in laboratory and astrophysical plasmas. A central question concerns why the observed reconnection rates are much faster than predictions made by classical theories, such as the Sweet-Parker model based on MHD with classical Spitzer resistivity. Often, the local resistivity is conjectured to be enhanced by micro-instabilities to accelerate reconnection rates either in the context of the Sweet-Parker model or by facilitating setup of the Pestchek model. Although it is commonly believed that there is plenty of free energy available at the reconnection region to destabilize some sort of micro-instability, a clear identification of this instability and its exact role in reconnection has never been established experimentally. We report the first such experimental evidence of a clear and positive correlation between magnetic fluctuations in the lower-hybrid frequency range and resistivity enhancement during fast reconnection in the low-collisionality regimes in the Magnetic Reconnection Experiment (MRX). The waves have been identified as right-hand polarized whistler waves, propagating obliquely to the reconnecting field, with a phase velocity comparable to the relative drift velocity. These waves are consistent with the modified two-stream instability driven by large drift speeds compared to the Alfven speed in high-beta plasmas. The short coherence length and large variation along the propagation direction indicate their strongly nonlinear nature.

Original languageEnglish (US)
Title of host publicationPlasmas in the Laboratory and in the Universe
Subtitle of host publicationNew Insights and New Challenges
EditorsRoberto Pozzoli, Daniela Farina, Giuseppe Bertin
PublisherAmerican Institute of Physics Inc.
Pages437-442
Number of pages6
ISBN (Electronic)0735401764
DOIs
StatePublished - Apr 6 2004
EventInternational Symposium on Plasmas in the Laboratory and in the Universe: New Insights and New Challenges - Como, Italy
Duration: Sep 16 2003Sep 19 2003

Publication series

NameAIP Conference Proceedings
Volume703
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherInternational Symposium on Plasmas in the Laboratory and in the Universe: New Insights and New Challenges
CountryItaly
CityComo
Period9/16/039/19/03

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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