Experimental investigation of the trigger problem in magnetic reconnection

Journal Article · Sun May 15 04:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3562937· OSTI ID:21537857

Katz, Noam; Egedal, Jan; Fox, Will; Le, Ari; Vrublevskis, Arturs; Bonde, Jeff ^[1]

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1. Department of Physics/Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

Magnetic reconnection releases magnetic energy not only in steady state, but also in time-dependent and often explosive events. Here, we investigate the trigger mechanism for this explosive release by using a toroidal experiment in the strong guide-field regime. We observe spontaneous reconnection events with exponentially growing reconnection rates, and we characterize the full 3D dynamics of these events using multiple internal probes. The reconnection is asymmetric: it begins at one toroidal location and propagates around in both directions. The spontaneous onset is facilitated by an interaction between the x-line current channel and a global mode, which appears in the electrostatic potential. It is this mode which breaks axisymmetry and enables a localized decrease in x-line current. We apply a simple model - which relies on ion polarization currents for current continuity - to reproduce the exponential growth and compute the growth rate. The result agrees well with the experimental growth rate.

• OSTI ID: 21537857
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CLOSED PLASMA DEVICES
EXPLOSIVES
FLUID MECHANICS
HYDRODYNAMICS
MAGNETIC RECONNECTION
MAGNETOHYDRODYNAMICS
MECHANICS
PLASMA
PROBES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES