High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak

Molina Cabrera, P. A.; Labit, B.; Coda, S.; Porte, L.

doi:10.7910/DVN/CWP7FN

Title: High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak

Abstract

This publication presents high spatio-temporal resolution (mm/μs) density profile measurements of the pedestal top during type I, III, and small edge localized mode (ELM) H-mode plasmas in the Tokamak à Configuration Variable (TCV). These measurements were performed using a novel short-pulse reflectometer. Average inter-ELM density profiles are obtained via conditional averaging using the Dα trace as ELM indicator. Changes to the pedestal density profile gradients prior to type-III ELMs reveal unique pedestal dynamics leading to the ELM crash which can provide important experimental data for validation of non-linear MHD ELM simulations. The small-ELM scenario is found to feature a ∼25-35 kHz quasi-coherent density fluctuation near the separatrix rho_psi ∼0.993-1.05 not observed during a similar type-I ELM discharge. This oscillation is also found in low-field-side magnetic pick- up probes displaying a ballooning character and n=+1 toroidal mode number. This oscillation could help explain the markedly different pedestal dynamics observed in the small-ELM regime.

Authors:: Molina Cabrera, P. A.; Labit, B.; Coda, S.; Porte, L.

Publication Date:: Wed Jun 15 00:00:00 EDT 2022

DOE Contract Number:: SC0014264; SC0006419; SC0017381

Research Org.:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center

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

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

OSTI Identifier:: 1889450

DOI:: https://doi.org/10.7910/DVN/CWP7FN

Citation Formats


                    Molina Cabrera, P. A., Labit, B., Coda, S., and Porte, L. High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak.  United States: N. p., 2022. 
        Web.  doi:10.7910/DVN/CWP7FN.

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                    Molina Cabrera, P. A., Labit, B., Coda, S., & Porte, L. High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak.  United States.  doi:https://doi.org/10.7910/DVN/CWP7FN

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                    Molina Cabrera, P. A., Labit, B., Coda, S., and Porte, L. 2022.  
"High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak".  United States.  doi:https://doi.org/10.7910/DVN/CWP7FN.  https://www.osti.gov/servlets/purl/1889450. Pub date:Wed Jun 15 00:00:00 EDT 2022

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@article{osti_1889450,

  title        = {High resolution density pedestal measurements during edge localized modes by short-pulse reflectometry in the TCV tokamak},

  author       = {Molina Cabrera, P. A. and Labit, B. and Coda, S. and Porte, L.},

  abstractNote = {This publication presents high spatio-temporal resolution (mm/μs) density profile measurements of the pedestal top during type I, III, and small edge localized mode (ELM) H-mode plasmas in the Tokamak à Configuration Variable (TCV). These measurements were performed using a novel short-pulse reflectometer. Average inter-ELM density profiles are obtained via conditional averaging using the Dα trace as ELM indicator. Changes to the pedestal density profile gradients prior to type-III ELMs reveal unique pedestal dynamics leading to the ELM crash which can provide important experimental data for validation of non-linear MHD ELM simulations. The small-ELM scenario is found to feature a ∼25-35 kHz quasi-coherent density fluctuation near the separatrix rho_psi ∼0.993-1.05 not observed during a similar type-I ELM discharge. This oscillation is also found in low-field-side magnetic pick- up probes displaying a ballooning character and n=+1 toroidal mode number. This oscillation could help explain the markedly different pedestal dynamics observed in the small-ELM regime.},

  doi          = {10.7910/DVN/CWP7FN},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Wed Jun 15 00:00:00 EDT 2022},

  month        = {Wed Jun 15 00:00:00 EDT 2022}

}

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