Spatially resolved ion heating measurements during a sawtooth crash on the Madison Symmetric Torus (MST)

S. Gangadhara, D. Craig, D. A. Ennis, D. J. Den Hartog, G. Fiksel, D. J. Holly, S. C. Prager, V. V. Mirnov, V. A. Svidzinski

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Ion tem-perature measurements with good spa- tial and temporal resolution have been made for the first time during a fast re- connection event (i.e. sawtooth crash) on MST. Measurements indicate the presence of strong ion heating during the crash, and that the heating occurs over a large fraction of the plasma vol- ume. This heating takes place over a short time scale, relative to the ion-ion collision time. There is also indication that this heat- ing is stronger for impurities than for the bulk. A number of theories are being developed to explain this heating, including viscous damp- ing of fluctuations and electric field acceleration of ions during the reconnection (though for viscous damping to be effective, large, localized flows are necessary, which have yet to be observed experimentally). To facilitate better comparison with theory, a number of upgrades are currently being performed to the CHERS system. They include: (1) addition of a toroidal CHERS view, to allow for measurement of T∥/T⊥, an important parameter in many heating theories; (2) commissioning of a new long-pulse (20 ms) DNB, which will provide an improve- ment in the single-shot signal-to-noise and allow for more sawtooth crash data to be collected in a single experimental run; (3) studying ion heating during other plasma phenomena - such as in plasmas with reduced relaxation, in which initial observations suggest that anomalous heating may be small - to increase understanding of heat sources and sinks and ion transport in MST.

Original languageEnglish (US)
Title of host publication32nd EPS Conference on Plasma Physics 2005, EPS 2005, Held with the 8th International Workshop on Fast Ignition of Fusion Targets - Europhysics Conference Abstracts
Pages2086-2089
Number of pages4
StatePublished - Dec 1 2005
Externally publishedYes
Event32nd European Physical Society Conference on Plasma Physics and Controlled Fusion combined with the 8th International Workshop on Fast Ignition of Fusion Targets - Tarragona, Spain
Duration: Jun 27 2005Jul 1 2005

Publication series

Name32nd EPS Conference on Plasma Physics 2005, EPS 2005, Held with the 8th International Workshop on Fast Ignition of Fusion Targets - Europhysics Conference Abstracts
Volume3

Other

Other32nd European Physical Society Conference on Plasma Physics and Controlled Fusion combined with the 8th International Workshop on Fast Ignition of Fusion Targets
CountrySpain
CityTarragona
Period6/27/057/1/05

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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