Correlation between the relative blob fraction and plasma parameters in NSTX

Zweben, S. J.; Banerjee, S.; Bisai, N.; Diallo, A.; Lampert, M.; LeBlanc, B.; Myra, J. R.; Russell, D. A.

doi:10.1063/5.0074261

Title: Correlation between the relative blob fraction and plasma parameters in NSTX

Abstract

Here, we present a simple analysis of the fraction of blobs observed in the scrape-off layer of NSTX and calculates the correlation between this blob fraction and various plasma parameters. The measurements were made using the gas puff imaging (GPI) diagnostic on a database of 103 shots from 2010 with neutral beam power P_NBI = 0–6 MW. The blob fraction ranged from f_b = 0.1% to 4.8%, where f_b is defined as the fraction of time the GPI signal was larger than three times its average value within 0–7.5 cm outside the separatrix. The blob fraction generally decreased with increasing neutral beam injection power and was lower on average in H-mode plasmas than Ohmic and L-mode plasmas. The blob fraction had its highest correlation with the measured poloidal turbulence velocity and its radial gradient just inside the separatrix. This is in part consistent with a model in which the blob generation rate increases with the poloidal velocity shear.

Authors:

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^[1];

^[1]; LeBlanc, B. ^[1];

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Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Institute for Plasma Research (India); Homi Bhabha National Institute (HBNI) (India)
Lodestar Research Corporation, Boulder, CO (United States)

Publication Date:: Tue Jan 18 00:00:00 EST 2022

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

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

OSTI Identifier:: 1886887

Alternate Identifier(s):: OSTI ID: 1840781

Grant/Contract Number:: AC02-09CH11466; FG02-97ER54392; AC02 09CH11466

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 29; Journal Issue: 1; 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; plasma confinement; tokamaks

Citation Formats


                    Zweben, S. J., Banerjee, S., Bisai, N., Diallo, A., Lampert, M., LeBlanc, B., Myra, J. R., and Russell, D. A. Correlation between the relative blob fraction and plasma parameters in NSTX.  United States: N. p., 2022. 
Web.  doi:10.1063/5.0074261.

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                    Zweben, S. J., Banerjee, S., Bisai, N., Diallo, A., Lampert, M., LeBlanc, B., Myra, J. R., & Russell, D. A. Correlation between the relative blob fraction and plasma parameters in NSTX.  United States.  https://doi.org/10.1063/5.0074261

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                    Zweben, S. J., Banerjee, S., Bisai, N., Diallo, A., Lampert, M., LeBlanc, B., Myra, J. R., and Russell, D. A. Tue .  
"Correlation between the relative blob fraction and plasma parameters in NSTX".  United States.  https://doi.org/10.1063/5.0074261.  https://www.osti.gov/servlets/purl/1886887.

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@article{osti_1886887,

  title        = {Correlation between the relative blob fraction and plasma parameters in NSTX},

  author       = {Zweben, S. J. and Banerjee, S. and Bisai, N. and Diallo, A. and Lampert, M. and LeBlanc, B. and Myra, J. R. and Russell, D. A.},

  abstractNote = {Here, we present a simple analysis of the fraction of blobs observed in the scrape-off layer of NSTX and calculates the correlation between this blob fraction and various plasma parameters. The measurements were made using the gas puff imaging (GPI) diagnostic on a database of 103 shots from 2010 with neutral beam power PNBI = 0–6 MW. The blob fraction ranged from fb = 0.1% to 4.8%, where fb is defined as the fraction of time the GPI signal was larger than three times its average value within 0–7.5 cm outside the separatrix. The blob fraction generally decreased with increasing neutral beam injection power and was lower on average in H-mode plasmas than Ohmic and L-mode plasmas. The blob fraction had its highest correlation with the measured poloidal turbulence velocity and its radial gradient just inside the separatrix. This is in part consistent with a model in which the blob generation rate increases with the poloidal velocity shear.},

  doi          = {10.1063/5.0074261},

  journal      = {Physics of Plasmas},

  number       = 1,

  volume       = 29,

  place        = {United States},

  year         = {Tue Jan 18 00:00:00 EST 2022},

  month        = {Tue Jan 18 00:00:00 EST 2022}

}

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