Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D

Eldon, David; Boivin, Rejean L.; Groebner, Richard J.; Osborne, Thomas H.; Snyder, Philip B.; Turnbull, Alan D.; Tynan, George R.; Boedo, Jose A.; Burrell, Keith H.; Kolemen, Egemen; Schmitz, Lothar; Wilson, Howard R.

doi:10.1063/1.4919942

Title: Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D

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Abstract

Here, the H-mode transport barrier allows confinement of roughly twice as much energy as in an L-mode plasma. Termination of H-mode necessarily requires release of this energy, and the timescale of that release is of critical importance for the lifetimes of plasma facing components in next step tokamaks such as ITER. H-L transition sequences in modern tokamaks often begin with a transient outburst which appears to be superficially similar to and has sometimes been referred to as a type-I edge localized mode (ELM). Type-I ELMs have been shown to be consistent with ideal peeling ballooning instability and are characterized by significant (up to ~50%) reduction of pedestal height on short (~1 ms) timescales. Knowing whether or not this type of instability is present during H-L back transitions will be important for planning for plasma ramp-down in ITER. This paper presents tests of pre-transition experimental data against ideal peeling-ballooning stability calculations with the ELITE code and supports 2 those results with secondary experiments that together show that the transient associated with the H-L transition is not triggered by the same physics as are type-I ELMs.

Authors:

^[1]; Boivin, Rejean L. ^[2]; Groebner, Richard J. ^[2]; Osborne, Thomas H. ^[2]; Snyder, Philip B. ^[2];

^[2]; Tynan, George R. ^[3]; Boedo, Jose A. ^[3];

^[2]; Kolemen, Egemen ^[4]; Schmitz, Lothar ^[5]; Wilson, Howard R. ^[6]

Univ. of California San Diego, La Jolla, CA (United States); Princeton Univ., Princeton, NJ (United States)
General Atomics, San Diego, CA (United States)
Univ. of California San Diego, La Jolla, CA (United States)
Princeton Univ., Princeton, NJ (United States)
Univ. of California, Los Angeles, CA (United States)
Univ. of York, York (United Kingdom)

Publication Date:: Thu May 14 00:00:00 EDT 2015

Research Org.:: General Atomics, San Diego, CA (United States)

Sponsoring Org.:: USDOE Office of Nuclear Energy (NE)

OSTI Identifier:: 1356320

Alternate Identifier(s):: OSTI ID: 1228230

Grant/Contract Number:: FC02-04ER54698; AC02-09CH11466; FG02-07ER54917; FG02-08ER54984

Resource Type:: Accepted Manuscript

Journal Name:: Physics of Plasmas

Additional Journal Information:: Journal Volume: 22; 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

Citation Formats


                    Eldon, David, Boivin, Rejean L., Groebner, Richard J., Osborne, Thomas H., Snyder, Philip B., Turnbull, Alan D., Tynan, George R., Boedo, Jose A., Burrell, Keith H., Kolemen, Egemen, Schmitz, Lothar, and Wilson, Howard R. Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D.  United States: N. p., 2015. 
Web.  doi:10.1063/1.4919942.

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                    Eldon, David, Boivin, Rejean L., Groebner, Richard J., Osborne, Thomas H., Snyder, Philip B., Turnbull, Alan D., Tynan, George R., Boedo, Jose A., Burrell, Keith H., Kolemen, Egemen, Schmitz, Lothar, & Wilson, Howard R. Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D.  United States.  https://doi.org/10.1063/1.4919942

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                    Eldon, David, Boivin, Rejean L., Groebner, Richard J., Osborne, Thomas H., Snyder, Philip B., Turnbull, Alan D., Tynan, George R., Boedo, Jose A., Burrell, Keith H., Kolemen, Egemen, Schmitz, Lothar, and Wilson, Howard R. Thu .  
"Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D".  United States.  https://doi.org/10.1063/1.4919942.  https://www.osti.gov/servlets/purl/1356320.

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@article{osti_1356320,

  title        = {Investigation of peeling-ballooning stability prior to transient outbursts accompanying transitions out of H-mode in DIII-D},

  author       = {Eldon, David and Boivin, Rejean L. and Groebner, Richard J. and Osborne, Thomas H. and Snyder, Philip B. and Turnbull, Alan D. and Tynan, George R. and Boedo, Jose A. and Burrell, Keith H. and Kolemen, Egemen and Schmitz, Lothar and Wilson, Howard R.},

  abstractNote = {Here, the H-mode transport barrier allows confinement of roughly twice as much energy as in an L-mode plasma. Termination of H-mode necessarily requires release of this energy, and the timescale of that release is of critical importance for the lifetimes of plasma facing components in next step tokamaks such as ITER. H-L transition sequences in modern tokamaks often begin with a transient outburst which appears to be superficially similar to and has sometimes been referred to as a type-I edge localized mode (ELM). Type-I ELMs have been shown to be consistent with ideal peeling ballooning instability and are characterized by significant (up to ~50%) reduction of pedestal height on short (~1 ms) timescales. Knowing whether or not this type of instability is present during H-L back transitions will be important for planning for plasma ramp-down in ITER. This paper presents tests of pre-transition experimental data against ideal peeling-ballooning stability calculations with the ELITE code and supports 2 those results with secondary experiments that together show that the transient associated with the H-L transition is not triggered by the same physics as are type-I ELMs.},

  doi          = {10.1063/1.4919942},

  journal      = {Physics of Plasmas},

  number       = 5,

  volume       = 22,

  place        = {United States},

  year         = {Thu May 14 00:00:00 EDT 2015},

  month        = {Thu May 14 00:00:00 EDT 2015}

}

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