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Title: Parallel electron force balance and the L-H transition

Abstract

In one popular description of the L-H transition, energy transfer to the mean flows directly depletes turbulence fluctuation energy, resulting in suppression of the turbulence and a corresponding transport bifurcation. However, electron parallel force balance couples nonzonal velocity fluctuations with electron pressure fluctuations on rapid timescales, comparable with the electron transit time. For this reason, energy in the nonzonal velocity stays in a fairly fixed ratio to the free energy in electron density fluctuations, at least for frequency scales much slower than electron transit. In order for direct depletion of the energy in turbulent fluctuations to cause the L-H transition, energy transfer via Reynolds stress must therefore drain enough energy to significantly reduce the sum of the free energy in nonzonal velocities and electron pressure fluctuations. At low k, the electron thermal free energy is much larger than the energy in nonzonal velocities, posing a stark challenge for this model of the L-H transition.

Authors:
ORCiD logo [1]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
OSTI Identifier:
1366720
DOE Contract Number:  
AC02-09CH11466
Resource Type:
Data
Resource Relation:
Related Information: Physics of Plasmas, Vol. 23, p. 054505 (May 2016)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; L-H transition Tokamak Reynolds stress Zonal flows

Citation Formats

Stotlzfus-Dueck, T. Parallel electron force balance and the L-H transition. United States: N. p., 2016. Web. doi:10.11578/1366720.
Stotlzfus-Dueck, T. Parallel electron force balance and the L-H transition. United States. doi:10.11578/1366720.
Stotlzfus-Dueck, T. Sun . "Parallel electron force balance and the L-H transition". United States. doi:10.11578/1366720. https://www.osti.gov/servlets/purl/1366720.
@article{osti_1366720,
title = {Parallel electron force balance and the L-H transition},
author = {Stotlzfus-Dueck, T.},
abstractNote = {In one popular description of the L-H transition, energy transfer to the mean flows directly depletes turbulence fluctuation energy, resulting in suppression of the turbulence and a corresponding transport bifurcation. However, electron parallel force balance couples nonzonal velocity fluctuations with electron pressure fluctuations on rapid timescales, comparable with the electron transit time. For this reason, energy in the nonzonal velocity stays in a fairly fixed ratio to the free energy in electron density fluctuations, at least for frequency scales much slower than electron transit. In order for direct depletion of the energy in turbulent fluctuations to cause the L-H transition, energy transfer via Reynolds stress must therefore drain enough energy to significantly reduce the sum of the free energy in nonzonal velocities and electron pressure fluctuations. At low k, the electron thermal free energy is much larger than the energy in nonzonal velocities, posing a stark challenge for this model of the L-H transition.},
doi = {10.11578/1366720},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {5}
}

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Works referenced in this record:

Parallel electron force balance and the L-H transition
journal, May 2016


    Works referencing / citing this record:

    Parallel electron force balance and the L-H transition
    journal, May 2016