Modelling the effect of divertor closure on detachment onset in DIII-D with the SOLPS code

Casali, L.; Sang, C.; Moser, A. L.; Covele, B. M.; Guo, H. Y.; Samuell, C.

doi:10.1002/ctpp.201700215

Modelling the effect of divertor closure on detachment onset in DIII-D with the SOLPS code

Journal Article · Thu Apr 26 00:00:00 EDT 2018 · Contributions to Plasma Physics

DOI:https://doi.org/10.1002/ctpp.201700215· OSTI ID:1491633

^[1]; Sang, C. ^[2]; Moser, A. L. ^[3]; Covele, B. M. ^[3]; Guo, H. Y. ^[3]; Samuell, C. ^[4]

Oak Ridge Associated Univ., Oak Ridge, TN (United States)
Dalian Univ. of Technology, Dalian (China). School of Physics
General Atomics, San Diego, CA (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

SOLPS modelling has shown that divertor plasma detachment occurs at a lower upstream separatrix density in the more closed DIII-D upper divertor than the open lower divertor, demonstrating the utility of the divertor closure in widening the range of acceptable densities for adequate heat handling. To achieve reduced heat flux and erosion at the plasma-facing components, future devices will need to operate in at least partially detached divertor conditions . Two-dimensional fluid plasma models coupled to Monte Carlo neutral transport simulations, such as SOLPS, have been widely used to predict the onset of detachment. In modelling the DIII-D discharges, the cross-field transport coefficients are constrained to reproduce the experimental upstream profiles. The closed divertor has been modelled with the same input parameters of the open divertor, allowing a direct comparison of the target conditions in both geometries. SOLPS simulations indicate that a higher molecular density correlates strongly with lower electron temperatures. The increased closure of the upper divertor improves the trapping of neutrals, thereby reducing the power density deposited at the target and facilitating detachment, in agreement with experimental observations.

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

Sponsoring Organization:: USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC52-07NA27344; FC02-04ER54698

OSTI ID:: 1491633

Alternate ID(s):: OSTI ID: 1434964
OSTI ID: 22747259

Report Number(s):: LLNL-JRNL--751782; 936705

Journal Information:: Contributions to Plasma Physics, Journal Name: Contributions to Plasma Physics Journal Issue: 6-8 Vol. 58; ISSN 0863-1042

Publisher:: WileyCopyright Statement

Country of Publication:: United States

Language:: English

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