Mechanisms of Impulsiive Magnetic Reconnection: Global and Local Aspects
Authors: Masaaki Yamada
Abstract:
The global and local aspects of mechanisms of impulsive magnetic reconnection are discussed
focusing on results from a dedicated laboratory experiment, MRX (Magnetic Reconnection
Experiment), as well as fusion experiments. Possible application of the present analysis to
reconnection phenomena in solar and space plasmas is also discussed. An external force which
drives internal current in a fusion plasma causes magnetic flux to accumulate in a core section of
the plasma (flux build-up). When the flux build-up generates a magnetic profile that satisfies a
condition for a global magnetohydrodynamic instability to develop, reconnection takes place in an
induced current layer generated by the instability leading to a global self-organization of the
plasma. Generally the flux build-up phase is significantly longer than the reconnection time,
&tauH >> &tauRec, thus making the waveform of flux evolution or other plasma parameters sawtooth shaped.
In the reconnection layer of collisionless plasmas, the two fluid dynamics would lead to the formation
of a narrow electron current channel which tends to become unstable against micro-instabilities, leading
to an unsteady or impulsive reconnection. A common feature of impulsive reconnection after flux
build-up is presented. (c) 2011 American Institute of Physics . [doi:10.1063/1.3658034 ]
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Submitted to: American Institute of Physics (November 2011) Presented at: US-Japan Workshop on Magnetic Reconnection, Nara, Japan (2010)
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