Study of Disruptive Current Layers in the Magnetic Reconnection Experiment (MRX)

One of the key open questions in magnetic reconnection is the nature of the mechanism that governs the reconnection rate in real astrophysical and laboratory systems. Comparisons between fully kinetic 2-D simulations of the Magnetic Reconnection Experiment (MRX) and experimental data indicate that three-dimensional dynamics, such as current layer disruptions recently observed in MRX, may play a key role in resolving an important discrepancy in the reconnection rate and layer width [1,2,3]. These disruptions are often associated with fluctuations in the lower hybrid frequency range and a rapid local reconnection rate. Some discharges also display ``O-point'' signatures consistent with magnetic island like structures. The present research explores the relationship between the disruptions and fluctuations in the context of the reconnection rate problem. Comparisons with 3-D simulations are ongoing in order to determine what key physics is responsible for the broader current layers observed in the experiment. [1] Y. Ren, et al., Phys. Plasmas 15, 082113 (2008). [2] S. Dorfman, et al., Phys. Plasmas 15, 102107 (2008). [3] V. Roytershteyn, et al., Phys. Plasmas 17, 055706 (2010). Supported by NDSEG, DOE, NASA, and NSF.