Microtearing instabilities and electron transport in the NSTX spherical tokamak

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

Abstract

In summary, we have shown that the observed electron thermal conductivity in one type of NSTX discharge can be explained by the magnetic fluctuations from microtearing instabilities. These modes saturate at large amplitude due to the low magnetic field; they produce global stochastic magnetic fields, and therefore Eq.(1) is applicable. This explains the good agreement between the theoretical and the observed electron thermal conductivity over the entire region where the microtearing mode is the fastest growing instability with 0.3 ≤ kθρi ≤ 1. NSTX has the flexibility to operate in many regimes. This instability could be suppressed by reversed magnetic shear, by raising the electron temperature such that νe < ω*e, or by operating at higher magnetic field to reduce the saturation amplitude. This result does not rule out ETG turbulence in controlling electron transport in NSTX. ETG modes are calculated to be important in other discharges and/or at other locations.

Original languageEnglish (US)
Title of host publication34th EPS Conference on Plasma Physics 2007, EPS 2007 - Europhysics Conference Abstracts
Pages881-884
Number of pages4
Edition2
StatePublished - 2007
Event34th European Physical Society Conference on Plasma Physics 2007, EPS 2007 - Warsaw, Poland
Duration: Jul 2 2007Jul 6 2007

Publication series

Name34th EPS Conference on Plasma Physics 2007, EPS 2007 - Europhysics Conference Abstracts
Number2
Volume31

Other

Other34th European Physical Society Conference on Plasma Physics 2007, EPS 2007
Country/TerritoryPoland
CityWarsaw
Period7/2/077/6/07

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics

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