The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations

Cui, L.; Nazikian, Raffi; Grierson, B. A.; Belli, Emily A.; Evans, Todd E.; Logan, Nikolas C.; Orlov, Dmitri M.; Smith, Sterling P.; Staebler, Gary M.; Snyder, Philip B.

doi:10.1088/1741-4326/aa7efe

Title: The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations

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Abstract

Resonant magnetic perturbations (RMPs) are a leading method for edge localized modes (ELMs) Control in fusion plasmas. However they can also cause a rapid degradation in energy confinement. In this paper we show that the energy confinement in low collisionality ( e < 0.3) DIII-D ITER similar shape (ISS) plasmas often recovers after several energy confinement times for RMP amplitudes up to the threshold for ELM suppression. Immediately following the application of the RMP, the plasma stored energy decreases in proportion to the decrease in the line-averaged density during density ‘pump-out’. Later in the discharge confinement recovery is observed in the thermal ion channel and is correlated with the increase in the ion temperature at the top of the H-mode pedestal. A correlation between the inverse scale length of the ion temperature (a/LTi) and the E × B shearing rate at the top of the pedestal is seen during the confinement recovery phase. Transport analysis reveals that the confinement improvement in the ion channel results from the self-similarity in the ion temperature profiles in the plasma core combined with the observed increase in a/LTi in the plasma edge following density pump-out. In contrast the electron temperature scale length (a/LTe) remainsmore »« less

Authors:

Cui, L. ^[1]; Nazikian, Raffi ^[1]; Grierson, B. A. ^[1]; Belli, Emily A. ^[2]; Evans, Todd E. ^[2]; Logan, Nikolas C. ^[1]; Orlov, Dmitri M. ^[3]; Smith, Sterling P. ^[2]; Staebler, Gary M. ^[2]; Snyder, Philip B. ^[2]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
General Atomics, San Diego, CA (United States)
Univ. of California-San Diego, La Jolla, CA (United States)

Publication Date:: Tue Jul 11 00:00:00 EDT 2017

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)

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

OSTI Identifier:: 1373689

Alternate Identifier(s):: OSTI ID: 1390215

Grant/Contract Number:: AC02-09CH11466; FC02-04ER54698; FG02-05ER54809

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Fusion

Additional Journal Information:: Journal Volume: 57; Journal Issue: 11; Journal ID: ISSN 0029-5515

Publisher:: IOP Science

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    Cui, L., Nazikian, Raffi, Grierson, B. A., Belli, Emily A., Evans, Todd E., Logan, Nikolas C., Orlov, Dmitri M., Smith, Sterling P., Staebler, Gary M., and Snyder, Philip B. The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations.  United States: N. p., 2017. 
Web.  doi:10.1088/1741-4326/aa7efe.

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                    Cui, L., Nazikian, Raffi, Grierson, B. A., Belli, Emily A., Evans, Todd E., Logan, Nikolas C., Orlov, Dmitri M., Smith, Sterling P., Staebler, Gary M., & Snyder, Philip B. The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations.  United States.  https://doi.org/10.1088/1741-4326/aa7efe

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                    Cui, L., Nazikian, Raffi, Grierson, B. A., Belli, Emily A., Evans, Todd E., Logan, Nikolas C., Orlov, Dmitri M., Smith, Sterling P., Staebler, Gary M., and Snyder, Philip B. Tue .  
"The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations".  United States.  https://doi.org/10.1088/1741-4326/aa7efe.  https://www.osti.gov/servlets/purl/1373689.

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@article{osti_1373689,

  title        = {The energy confinement response of DIII-D plasmas to Resonant Magnetic Perturbations},

  author       = {Cui, L. and Nazikian, Raffi and Grierson, B. A. and Belli, Emily A. and Evans, Todd E. and Logan, Nikolas C. and Orlov, Dmitri M. and Smith, Sterling P. and Staebler, Gary M. and Snyder, Philip B.},

  abstractNote = {Resonant magnetic perturbations (RMPs) are a leading method for edge localized modes (ELMs) Control in fusion plasmas. However they can also cause a rapid degradation in energy confinement. In this paper we show that the energy confinement in low collisionality ( e < 0.3) DIII-D ITER similar shape (ISS) plasmas often recovers after several energy confinement times for RMP amplitudes up to the threshold for ELM suppression. Immediately following the application of the RMP, the plasma stored energy decreases in proportion to the decrease in the line-averaged density during density ‘pump-out’. Later in the discharge confinement recovery is observed in the thermal ion channel and is correlated with the increase in the ion temperature at the top of the H-mode pedestal. A correlation between the inverse scale length of the ion temperature (a/LTi) and the E × B shearing rate at the top of the pedestal is seen during the confinement recovery phase. Transport analysis reveals that the confinement improvement in the ion channel results from the self-similarity in the ion temperature profiles in the plasma core combined with the observed increase in a/LTi in the plasma edge following density pump-out. In contrast the electron temperature scale length (a/LTe) remains essentially unchanged in response to the application of the RMP. At significantly higher RMP levels the edge E × B shearing rate and a/LTi does not increase and the confinement does not recover following density pump-out.},

  doi          = {10.1088/1741-4326/aa7efe},

  journal      = {Nuclear Fusion},

  number       = 11,

  volume       = 57,

  place        = {United States},

  year         = {Tue Jul 11 00:00:00 EDT 2017},

  month        = {Tue Jul 11 00:00:00 EDT 2017}

}

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