Localized electron heating during magnetic reconnection in MAST

Significant increase in the plasma temperature above 1 keV was measured during the kilogauss magnetic field reconnection of two merging toroidal plasmas under the high-guide field and collision-less conditions. The electron temperature was observed to peak significantly at the X-point inside the cur...

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Bibliographic Details
Published in:Nuclear fusion 2016-10, Vol.56 (10), p.106019
Main Authors: Yamada, T., Tanabe, H., Watanabe, T.G., Hayashi, Y., Imazawa, R., Inomoto, M., Ono, Y., Gryaznevich, M., Scannell, R., Michael, C.
Format: Article
Language:English
Subjects:
magnetic reconnection
plasma heating
spherical tokamak
Thomson scattering
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Summary:Significant increase in the plasma temperature above 1 keV was measured during the kilogauss magnetic field reconnection of two merging toroidal plasmas under the high-guide field and collision-less conditions. The electron temperature was observed to peak significantly at the X-point inside the current sheet, indicating Joule heating caused by the toroidal electric field along the X-line. This peaked temperature increases significantly with the guide field, in agreement with the electron mean-free path calculation. The slow electron heating in the downstream suggests energy conversion from ions to electrons through ion-electron collisions in the bulk plasma as the second electron heating mechanism in the bulk plasma. The electron density profile clearly reveals the electron density pile-up / fast shock structures in the downstream of reconnection, suggesting energy conversion from ion flow energy to ion thermal energy as well as significant ion heating by reconnection outflow.
ISSN:0029-5515
1741-4326
DOI:10.1088/0029-5515/56/10/106019