Role of poloidal E  ×  B drift in divertor heat transport in DIII‐D

Jaervinen, A. E.; Allen, S. L.; Leonard, A. W.; McLean, A. G.; Moser, A. L.; Rognlien, T. D.; Samuell, C. M.

doi:10.1002/ctpp.201900111

Title: Role of poloidal E × B drift in divertor heat transport in DIII‐D

Abstract

Abstract Simulations for DIII‐D high confinement mode plasmas with the multifluid code UEDGE show a strong role of poloidal E × B drifts on divertor heat transport, challenging the paradigm of conduction‐limited scrape‐off layer (SOL) transport. While simulations with reduced drift magnitude are well aligned with the assumption that electron heat conduction dominates the SOL heat transport, simulations with drifts predict that the poloidal convective E × B heat transport dominates over electron heat conduction in both attached and detached conditions. As poloidal E × B flow propagates across magnetic field lines, poloidal transport with shallow magnetic pitch angles can reach values that are of the same order as would be provided by sonic flows parallel to the field lines. These flows can lead to strong convection‐dominated divertor heat transport, increasing the poloidal volume of radiative power front, consistent with previous measurements at DIII‐D. Due to these convective flows, the Lengyel integral approach, assuming zero convective fraction, is expected to provide a pessimistic estimate for the radiative capability of impurities in the divertor. For the DIII‐D simulations shown here, the Lengyel integral approach underestimates the radiated power by a factor of 6, indicating that, for reliable DIII‐D divertor power exhaustmore »« less

Authors:

Jaervinen, A. E. ^[1]; Allen, S. L. ^[1]; Leonard, A. W. ^[2]; McLean, A. G. ^[1]; Moser, A. L. ^[2]; Rognlien, T. D. ^[1]; Samuell, C. M. ^[1]

Lawrence Livermore National Laboratory Livermore California USA
General Atomics San Diego California USA

Publication Date:: Tue Dec 17 00:00:00 EST 2019

Research Org.:: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)

Sponsoring Org.:: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE Laboratory Directed Research and Development (LDRD) Program

OSTI Identifier:: 1786441

Alternate Identifier(s):: OSTI ID: 1647917; OSTI ID: 1786442

Report Number(s):: LLNL-JRNL-785037
Journal ID: ISSN 0863-1042; e201900111

Grant/Contract Number:: DE‐AC52‐07NA27344; DE‐FC02‐04ER54698; AC52-07NA27344; FC02-04ER54698; 17-ERD-020

Resource Type:: Published Article

Journal Name:: Contributions to Plasma Physics

Additional Journal Information:: Journal Name: Contributions to Plasma Physics Journal Volume: 60 Journal Issue: 5-6; Journal ID: ISSN 0863-1042

Publisher:: Wiley Blackwell (John Wiley & Sons)

Country of Publication:: Germany

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Divertor; Heat transport; Drifts; Convection; Conduction; Radiation

Citation Formats


                    Jaervinen, A. E., Allen, S. L., Leonard, A. W., McLean, A. G., Moser, A. L., Rognlien, T. D., and Samuell, C. M. Role of poloidal E  ×  B drift in divertor heat transport in DIII‐D.  Germany: N. p., 2019. 
Web.  doi:10.1002/ctpp.201900111.

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                    Jaervinen, A. E., Allen, S. L., Leonard, A. W., McLean, A. G., Moser, A. L., Rognlien, T. D., & Samuell, C. M. Role of poloidal E  ×  B drift in divertor heat transport in DIII‐D.  Germany.  https://doi.org/10.1002/ctpp.201900111

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                    Jaervinen, A. E., Allen, S. L., Leonard, A. W., McLean, A. G., Moser, A. L., Rognlien, T. D., and Samuell, C. M. Tue .  
"Role of poloidal E  ×  B drift in divertor heat transport in DIII‐D".  Germany.  https://doi.org/10.1002/ctpp.201900111.

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@article{osti_1786441,

  title        = {Role of poloidal E  ×  B drift in divertor heat transport in DIII‐D},

  author       = {Jaervinen, A. E. and Allen, S. L. and Leonard, A. W. and McLean, A. G. and Moser, A. L. and Rognlien, T. D. and Samuell, C. M.},

  abstractNote = {Abstract Simulations for DIII‐D high confinement mode plasmas with the multifluid code UEDGE show a strong role of poloidal E  ×  B drifts on divertor heat transport, challenging the paradigm of conduction‐limited scrape‐off layer (SOL) transport. While simulations with reduced drift magnitude are well aligned with the assumption that electron heat conduction dominates the SOL heat transport, simulations with drifts predict that the poloidal convective E  ×  B heat transport dominates over electron heat conduction in both attached and detached conditions. As poloidal E  ×  B flow propagates across magnetic field lines, poloidal transport with shallow magnetic pitch angles can reach values that are of the same order as would be provided by sonic flows parallel to the field lines. These flows can lead to strong convection‐dominated divertor heat transport, increasing the poloidal volume of radiative power front, consistent with previous measurements at DIII‐D. Due to these convective flows, the Lengyel integral approach, assuming zero convective fraction, is expected to provide a pessimistic estimate for the radiative capability of impurities in the divertor. For the DIII‐D simulations shown here, the Lengyel integral approach underestimates the radiated power by a factor of 6, indicating that, for reliable DIII‐D divertor power exhaust predictions, full two‐dimensional (2D) calculations, including drifts, would be necessary.},

  doi          = {10.1002/ctpp.201900111},

  journal      = {Contributions to Plasma Physics},

  number       = 5-6,

  volume       = 60,

  place        = {Germany},

  year         = {Tue Dec 17 00:00:00 EST 2019},

  month        = {Tue Dec 17 00:00:00 EST 2019}

}

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Works referenced in this record:

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$E \times B$ Flux Driven Detachment Bifurcation in the DIII-D Tokamak
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Title: Role of poloidal E × B drift in divertor heat transport in DIII‐D

Abstract

Citation Formats

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