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Title: Blob wakes in NSTX

Abstract

Transient small-scale structures were identified in the wake of blobs moving poloidally through the scrape-off layer of high-powered H-mode plasmas in NSTX, using the gas puff imaging (GPI) diagnostic. These blob wakes had a poloidal wavelength in the range of λpol = 3.5 ± 0.7 cm, which is significantly smaller than the average blob scale of Lpol ~12 cm, and the wakes had a poloidal velocity of Vpol = 1.5 ± 1.0 km/s in the electron diamagnetic direction, which is opposite to the blob poloidal velocity in these shots. These wakes were radially localized 0–4 cm outside the separatrix and occurred within ~50 μs after the passage of a blob through the GPI field of view. The clearest wakes were seen when the GPI viewing angle was well aligned with the local B field line, as expected for such small-scale structures given the diagnostic geometry. In conclusion, a plausible theoretical interpretation of the wakes is discussed: the observed wakes share some features of drift waves and/or drift-Alfvén waves which could be excited by the blobs.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [1]
+ Show Author Affiliations
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Lodestar Research Corp., Boulder, CO (United States)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1558756
Alternate Identifier(s):
OSTI ID: 1543031
Grant/Contract Number:  
AC02-09CH11466; AC52-07NA27344; FG02-02ER54678
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 7; 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

Citation Formats

Zweben, S. J., Myra, J. R., Diallo, A., Russell, D. A., Scotti, F., and Stotler, D. P. Blob wakes in NSTX. United States: N. p., 2019. Web. doi:10.1063/1.5094872.
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Zweben, S. J., Myra, J. R., Diallo, A., Russell, D. A., Scotti, F., & Stotler, D. P. Blob wakes in NSTX. United States. https://doi.org/10.1063/1.5094872
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Zweben, S. J., Myra, J. R., Diallo, A., Russell, D. A., Scotti, F., and Stotler, D. P. Wed . "Blob wakes in NSTX". United States. https://doi.org/10.1063/1.5094872. https://www.osti.gov/servlets/purl/1558756.
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@article{osti_1558756,
title = {Blob wakes in NSTX},
author = {Zweben, S. J. and Myra, J. R. and Diallo, A. and Russell, D. A. and Scotti, F. and Stotler, D. P.},
abstractNote = {Transient small-scale structures were identified in the wake of blobs moving poloidally through the scrape-off layer of high-powered H-mode plasmas in NSTX, using the gas puff imaging (GPI) diagnostic. These blob wakes had a poloidal wavelength in the range of λpol = 3.5 ± 0.7 cm, which is significantly smaller than the average blob scale of Lpol ~12 cm, and the wakes had a poloidal velocity of Vpol = 1.5 ± 1.0 km/s in the electron diamagnetic direction, which is opposite to the blob poloidal velocity in these shots. These wakes were radially localized 0–4 cm outside the separatrix and occurred within ~50 μs after the passage of a blob through the GPI field of view. The clearest wakes were seen when the GPI viewing angle was well aligned with the local B field line, as expected for such small-scale structures given the diagnostic geometry. In conclusion, a plausible theoretical interpretation of the wakes is discussed: the observed wakes share some features of drift waves and/or drift-Alfvén waves which could be excited by the blobs.},
doi = {10.1063/1.5094872},
journal = {Physics of Plasmas},
number = 7,
volume = 26,
place = {United States},
year = {Wed Jul 17 00:00:00 EDT 2019},
month = {Wed Jul 17 00:00:00 EDT 2019}
}
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Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1063/1.5094872
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Cited by: 2 works
Citation information provided by
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Figures / Tables:

Table 1 Table 1: shot list (time of peak GPI signal)
All figures and tables (15 total)
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Works referenced in this record:

Edge sheared flows and the dynamics of blob-filaments
journal, June 2013

On scrape off layer plasma transport
journal, May 2001

Experimental and numerical characterization of the turbulence in the scrape-off layer of MAST
journal, January 2013

Resistive modes in the edge and scrape-off layer of diverted tokamaks
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Two-dimensional turbulence cross-correlation functions in the edge of NSTX
journal, October 2017

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  • Physics of Plasmas, Vol. 24, Issue 10
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Effect of Magnetic Shear on Dissipative Drift-Wave Instabilities
journal, June 1978

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journal, June 2016

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journal, May 2002

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Blob structure and motion in the edge and SOL of NSTX
journal, January 2016

  • Zweben, S. J.; Myra, J. R.; Davis, W. M.
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On the role of filaments in perpendicular heat transport at the scrape-off layer
journal, July 2018

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journal, June 2008

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journal, January 2013

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journal, July 2018

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Characterization of the blob generation region and blobby transport in a stellarator
journal, April 2016

Invited Review Article: Gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion devices
journal, April 2017

  • Zweben, S. J.; Terry, J. L.; Stotler, D. P.
  • Review of Scientific Instruments, Vol. 88, Issue 4
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Convective transport by intermittent blob-filaments: Comparison of theory and experiment
journal, June 2011

  • D’Ippolito, D. A.; Myra, J. R.; Zweben, S. J.
  • Physics of Plasmas, Vol. 18, Issue 6
  • DOI: 10.1063/1.3594609

On the role of filaments in perpendicular heat transport at the Scrape-off Layer
text, January 2020

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    Figures / Tables found in this record:

    Table 1 (p. 23)table
    Table II (p. 23)table
    Fig. 1 (p. 31)figure
    Fig. 2(a) (p. 32)figure
    Fig. 2(b) (p. 33)figure
    Fig. 3 (p. 34)figure
    Fig. 4 (p. 35)figure
    Fig. 5 (p. 36)figure
    Fig. 6(a) (p. 37)figure
    Fig. 6(b) (p. 38)figure
    Fig. 7 (p. 39)figure
    Fig. 8 (p. 40)figure
    Fig. 9 (p. 41)figure
    Fig. 10 (p. 42)figure
    Fig. 11 (p. 43)figure
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