Parallel electron force balance and the L-H transition

Stotlzfus-Dueck, T.

doi:10.11578/1366720

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:

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:: 2016-05-01

DOE Contract Number:: AC02-09CH11466

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; L-H transition Tokamak Reynolds stress Zonal flows

Keywords:: L-H transition Tokamak Reynolds stress Zonal flows

OSTI Identifier:: 1366720

DOI:: https://doi.org/10.11578/1366720

Citation Formats


                    Stotlzfus-Dueck, T. Parallel electron force balance and the L-H transition.  United States: N. p., 2016. 
        Web.  doi:10.11578/1366720.

Copy to clipboard


                    Stotlzfus-Dueck, T. Parallel electron force balance and the L-H transition.  United States.  doi:https://doi.org/10.11578/1366720

Copy to clipboard


                    Stotlzfus-Dueck, T. 2016.  
"Parallel electron force balance and the L-H transition".  United States.  doi:https://doi.org/10.11578/1366720.  https://www.osti.gov/servlets/purl/1366720. Pub date:Sun May 01 00:00:00 EDT 2016

Copy to clipboard


                    
@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}

}

Copy to clipboard

Dataset:

View Dataset

DOI: https://doi.org/10.11578/1366720

Save / Share:

Export Metadata

Save to My Library

Works referenced in this record: