title: Cause of sudden magnetic reconnection in a laboratory plasma.
abstract: The cause for sudden reconnection in reversed field pinch plasmas is determined experimentally for two cases: large reconnection events (the sawtooth crash) and small reconnection events during improved confinement. We measure the term in the MHD equations which represents the driving (or damping) of edge tearing modes due to the axisymmetric magnetic field. The term is negative for large reconnection events (the modes are stable, implying that reconnection may be driven by nonlinear coupling to other modes) and positive for small reconnection events (modes are unstable, reconnection is spontaneous).
authors.affiliation: University of Wisconsin-Madison and the Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, 1150 University Avenue, Madison, WI 53706, USA.
authors.forename: S
authors.initials: S
authors.lastname: Choi
authors.forename: D
authors.initials: D
authors.lastname: Craig
authors.forename: F
authors.initials: F
authors.lastname: Ebrahimi
authors.forename: S C
authors.initials: SC
authors.lastname: Prager