Observation of reduced electron-temperature fluctuations in the core of H-mode plasmas

L Schmitz; A E White; T A Carter; W A Peebles; T L Rhodes; K H Burrell; W Solomon; G M Staebler

doi:10.1103/PhysRevLett.100.035002

Observation of reduced electron-temperature fluctuations in the core of H-mode plasmas

Phys Rev Lett. 2008 Jan 25;100(3):035002. doi: 10.1103/PhysRevLett.100.035002. Epub 2008 Jan 23.

Authors

L Schmitz¹, A E White, T A Carter, W A Peebles, T L Rhodes, K H Burrell, W Solomon, G M Staebler

Affiliation

¹ Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, CA 90024-2704, USA.

PMID: 18232989
DOI: 10.1103/PhysRevLett.100.035002

Abstract

Core electron-temperature fluctuations [0.5%< or =T[over ]_(e)/T_(e)< or =2%, k_(theta)rho_(s)< or =0.3 in neutral-beam-heated low confinement-mode (L-mode) plasmas] are observed to decrease by at least a factor of 4 in standard and quiescent high-confinement-mode (H-mode and QH-mode) regimes in the DIII-D tokamak (r/a=0.7). These fluctuations are attributed to ion temperature gradient (ITG) modes stabilized by rotational shear at the H-mode transition. The simultaneous reduction in electron heat diffusivity (chi_(e)(QH)/chi_(e)(L)<0.25) suggests that T[over ]_(e) fluctuations can contribute significantly to L-mode electron heat transport.