Experimental study of the Hall effect and electron diffusion region during magnetic reconnection in a laboratory plasma
- Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
The Hall effect during magnetic reconnection without an external guide field has been extensively studied in the laboratory plasma of the Magnetic Reconnection Experiment [M. Yamada et al., Phys. Plasmas 4, 1936 (1997)] by measuring its key signature, an out-of-plane quadrupole magnetic field, with magnetic probe arrays whose spatial resolution is on the order of the electron skin depth. The in-plane electron flow is deduced from out-of-plane magnetic field measurements. The measured in-plane electron flow and numerical results are in good agreement. The electron diffusion region is identified by measuring the electron outflow channel. The width of the electron diffusion region scales with the electron skin depth ({approx}5.5-7.5c/{omega}{sub pe}) and the peak electron outflow velocity scales with the electron Alfven velocity ({approx}0.12-0.16V{sub eA}), independent of ion mass. The measured width of the electron diffusion region is much wider and the observed electron outflow is much slower than those obtained in 2D numerical simulations. It is found that the classical and anomalous dissipation present in the experiment can broaden the electron diffusion region and slow the electron outflow. As a consequence, the electron outflow flux remains consistent with numerical simulations. The ions, as measured by a Mach probe, have a much wider outflow channel than the electrons, and their outflow is much slower than the electron outflow everywhere in the electron diffusion region.
- OSTI ID:
- 21120494
- Journal Information:
- Physics of Plasmas, Vol. 15, Issue 8; Other Information: DOI: 10.1063/1.2936269; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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