Localized electron heating during magnetic reconnection in MAST. (16th August 2016)

• Record Type: Journal Article
• Authors: Yamada, T.; Tanabe, H.; Watanabe, T.G.; Hayashi, Y.; Imazawa, R.; Inomoto, M.; Ono, Y.; Gryaznevich, M.; Scannell, R.; Michael, C.
• Other Names: collab.
• Is Part Of: Nuclear fusion. Volume 56:Number 10(2016:Oct.)
• Publication Date: 2016-08-16
• Subjects: spherical tokamak -- magnetic reconnection -- plasma heating -- Thomson scattering; Nuclear fusion -- Periodicals; 621.48405
• DOI: 10.1088/0029-5515/56/10/106019
• Languages: English
• ISSNs: 0029-5515

Abstract

Abstract: 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.