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

Abstract

In one popular paradigm for 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. To quantitatively evaluate this mechanism, one must remember that 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. Furthermore, 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:
 [1]
  1. Princeton Univ., Princeton, NJ (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1303849
Alternate Identifier(s):
OSTI ID: 1254197
Grant/Contract Number:  
AC02-09CH11466
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; energy transfer; free energy; Reynolds stress modeling; shear flows; turbulence effects

Citation Formats

Stoltzfus-Dueck, T. Parallel electron force balance and the L-H transition. United States: N. p., 2016. Web. doi:10.1063/1.4951015.
Stoltzfus-Dueck, T. Parallel electron force balance and the L-H transition. United States. doi:10.1063/1.4951015.
Stoltzfus-Dueck, T. Mon . "Parallel electron force balance and the L-H transition". United States. doi:10.1063/1.4951015. https://www.osti.gov/servlets/purl/1303849.
@article{osti_1303849,
title = {Parallel electron force balance and the L-H transition},
author = {Stoltzfus-Dueck, T.},
abstractNote = {In one popular paradigm for 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. To quantitatively evaluate this mechanism, one must remember that 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. Furthermore, 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 = {10.1063/1.4951015},
journal = {Physics of Plasmas},
number = 5,
volume = 23,
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
dataset, January 2016

  • Stoltzfus-Dueck, T.
  • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  • DOI: 10.11578/1562067

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journal, April 1994


Zonal flow production in the L–H transition in Alcator C-Mod
journal, May 2014


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journal, January 2016


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journal, February 1983


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journal, November 2003


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journal, June 1995

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  • Physics of Plasmas, Vol. 2, Issue 6
  • DOI: 10.1063/1.871264

Nonadiabatic electron response in the Hasegawa-Wakatani equations
journal, August 2013

  • Stoltzfus-Dueck, T.; Scott, B. D.; Krommes, J. A.
  • Physics of Plasmas, Vol. 20, Issue 8
  • DOI: 10.1063/1.4816807

    Works referencing / citing this record:

    Nonadiabatic electron response in the Hasegawa-Wakatani equations
    journal, August 2013

    • Stoltzfus-Dueck, T.; Scott, B. D.; Krommes, J. A.
    • Physics of Plasmas, Vol. 20, Issue 8
    • DOI: 10.1063/1.4816807

    Zonal flow production in the L–H transition in Alcator C-Mod
    journal, May 2014


    Recent progress towards a physics-based understanding of the H-mode transition
    journal, January 2016


    Influence of sheared poloidal rotation on edge turbulence
    journal, January 1990

    • Biglari, H.; Diamond, P. H.; Terry, P. W.
    • Physics of Fluids B: Plasma Physics, Vol. 2, Issue 1
    • DOI: 10.1063/1.859529

    Parallel electron force balance and the L-H transition
    dataset, January 2016

    • Stoltzfus-Dueck, T.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1562067

    A review of theories of the L-H transition
    journal, December 1999


    Advances in the simulation of toroidal gyro‐Landau fluid model turbulence
    journal, June 1995

    • Waltz, R. E.; Kerbel, G. D.; Milovich, J.
    • Physics of Plasmas, Vol. 2, Issue 6
    • DOI: 10.1063/1.871264

    Parallel electron force balance and the L-H transition
    dataset, January 2016

    • Stotlzfus-Dueck, T.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1366720

    Parallel electron force balance and the L-H transition
    dataset, January 2016

    • Stotlzfus-Dueck, T.
    • Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
    • DOI: 10.11578/1366720