Modeling Snowflake Divertors in MAST-U Tokamak

Khrabry, A. I.; Soukhanovskii, V. A.; Rognlien, T. D.; Umansky, M. V.; Moulton, D.; Harrison, J. R.

doi:10.1088/1741-4326/ac3364

Modeling Snowflake Divertors in MAST-U Tokamak

Journal Article · Thu Dec 02 00:00:00 EST 2021 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ac3364· OSTI ID:1860701

^[1]; ^[1]; Rognlien, T. D. ^[1]; Umansky, M. V. ^[1]; Moulton, D. ^[2]; ^[2]

Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Culham Centre for Fusion Energy, Abingdon (United Kingdom)

We report that in a snowflake (SF) divertor, two magnetic field nulls are placed close to each other, creating four strike points (SPs) compared to two in a standard X-point divertor. In preparation for MAST-U experiments, magnetic configurations with the standard and SF divertors with various locations and separation distances of the nulls were modeled using the two-dimensional multi-fluid code UEDGE with a full plasma transport model featuring charge-state-resolved sputtered carbon impurities. The complex interplay of the plasma transport and magnetic configurations was comprehensively studied using a simple model for the theoretically predicted fast plasma mixing driven by the 'churning' mode instability in the two-null SF region. The modeling results show that (1) all SF-plus configurations and SF-minus configuration with closely located nulls produce the same plasma parameters and heat fluxes at the same SPs; (2) SF divertors approach the outer and inner SP detachment conditions at lower upstream density w.r.t. the standard divertor; (3) heat flux profiles at primary SPs are substantially broadened and peak values are reduced in SF configurations w.r.t. SN divertors; this broadening becomes more pronounced with the fast plasma mixing increase.

View Accepted Manuscript (DOE)

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

Sponsoring Organization:: EURATOM; RCUK Energy Programme; USDOE National Nuclear Security Administration (NNSA)

Grant/Contract Number:: AC52-07NA27344

OSTI ID:: 1860701

Report Number(s):: LLNL-JRNL-822879; 1035485

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 1 Vol. 62; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (39)

Modelling the Effect of the Super-X Divertor in MAST Upgrade on Transition to Detachment and Distribution of Volumetric Power Losses: Modelling the Effect of the Super-X Divertor in MAST Upgrade on Transition to Detachment and Distribution of Volumetric Power Losses Havlíčková, E.; Wischmeier, M.; Fishpool, G. Contributions to Plasma Physics, Vol. 54, Issue 4-6 https://doi.org/10.1002/ctpp.201410025	journal	June 2014
Impurity release from low-Z materials under light particle bombardment Davis, J. W.; Haasz, A. A. Journal of Nuclear Materials, Vol. 241-243 https://doi.org/10.1016/S0022-3115(97)80029-3	journal	February 1997
Assessment of DEMO challenges in technology and physics Zohm, Hartmut Fusion Engineering and Design, Vol. 88, Issue 6-8 https://doi.org/10.1016/j.fusengdes.2013.01.001	journal	October 2013
New magnetic real time shape control for MAST Pangione, L.; McArdle, G.; Storrs, J. Fusion Engineering and Design, Vol. 88, Issue 6-8 https://doi.org/10.1016/j.fusengdes.2013.01.048	journal	October 2013
High performance plasma vertical position control system for upgraded MAST Cunningham, G. Fusion Engineering and Design, Vol. 88, Issue 12 https://doi.org/10.1016/j.fusengdes.2013.10.001	journal	December 2013
Multi-machine comparisons of H-mode separatrix densities and edge profile behaviour in the ITPA SOL and Divertor Physics Topical Group Kallenbach, A.; Asakura, N.; Kirk, A. Journal of Nuclear Materials, Vol. 337-339 https://doi.org/10.1016/j.jnucmat.2004.10.099	journal	March 2005
Influence of cross-field drifts and chemical sputtering on simulations of divertor particle and heat loads in ohmic and L-mode plasmas in DIII-D, AUG, and JET using UEDGE Groth, M.; Porter, G. D.; Rensink, M. E. Journal of Nuclear Materials, Vol. 415, Issue 1 https://doi.org/10.1016/j.jnucmat.2010.10.024	journal	August 2011
Modeling detachment physics in the NSTX snowflake divertor Meier, E. T.; Soukhanovskii, V. A.; Bell, R. E. Journal of Nuclear Materials, Vol. 463 https://doi.org/10.1016/j.jnucmat.2015.01.007	journal	August 2015
Interpretations of the impact of cross-field drifts on divertor flows in DIII-D with UEDGE Jaervinen, A. E.; Allen, S. L.; Groth, M. Nuclear Materials and Energy, Vol. 12 https://doi.org/10.1016/j.nme.2016.11.014	journal	August 2017
Experimental studies of the snowflake divertor in TCV Labit, B.; Canal, G. P.; Christen, N. Nuclear Materials and Energy, Vol. 12 https://doi.org/10.1016/j.nme.2017.03.013	journal	August 2017
Optimization of the snowflake divertor for power and particle exhaust on NSTX–U Vail, P. J.; Izacard, O.; Kolemen, E. Nuclear Materials and Energy, Vol. 19 https://doi.org/10.1016/j.nme.2019.03.003	journal	May 2019
Modeling snowflake divertors in MAST-U tokamak using UEDGE code Khrabry, A. I.; Soukhanovskii, V. A.; Rognlien, T. D. Nuclear Materials and Energy, Vol. 26 https://doi.org/10.1016/j.nme.2020.100896	journal	March 2021
Analysis of the progress to detachment in the divertor of the MAST tokamak Tabasso, A.; Dowling, J.; Ahn, J. -W Journal of Nuclear Materials, Vol. 313-316 https://doi.org/10.1016/s0022-3115(02)01480-0	journal	March 2003
A fully implicit, time dependent 2-D fluid code for modeling tokamak edge plasmas Rognlien, T. D.; Milovich, J. L.; Rensink, M. E. Journal of Nuclear Materials, Vol. 196-198 https://doi.org/10.1016/s0022-3115(06)80058-9	journal	December 1992
Classical drifts in the tokamak SOL and divertor: models and experiment Chankin, A. Journal of Nuclear Materials, Vol. 241-243, Issue 1 https://doi.org/10.1016/s0022-3115(96)00505-3	journal	February 1997
The atomic data and analysis structure Summers, H. P. Second international conference on atomic and molecular data and their applications, AIP Conference Proceedings https://doi.org/10.1063/1.1336288	conference	January 2000
Geometrical properties of a “snowflake” divertor Ryutov, D. D. Physics of Plasmas, Vol. 14, Issue 6 https://doi.org/10.1063/1.2738399	journal	June 2007
The magnetic field structure of a snowflake divertor Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D. Physics of Plasmas, Vol. 15, Issue 9 https://doi.org/10.1063/1.2967900	journal	September 2008
Snowflake divertor configuration studies in National Spherical Torus Experiment Soukhanovskii, V. A.; Bell, R. E.; Diallo, A. Physics of Plasmas, Vol. 19, Issue 8 https://doi.org/10.1063/1.4737117	journal	August 2012
The snowflake divertor Ryutov, D. D.; Soukhanovskii, V. A. Physics of Plasmas, Vol. 22, Issue 11 https://doi.org/10.1063/1.4935115	journal	November 2015
Toroidally symmetric plasma vortex at tokamak divertor null point Umansky, M. V.; Ryutov, D. D. Physics of Plasmas, Vol. 23, Issue 3 https://doi.org/10.1063/1.4943101	journal	March 2016
Overview of recent experimental results on MAST Lloyd, B.; Ahn, J-W; Akers, R. J. Nuclear Fusion, Vol. 43, Issue 12 https://doi.org/10.1088/0029-5515/43/12/012	journal	December 2003
Taming the plasma–material interface with the ‘snowflake’ divertor in NSTX Soukhanovskii, V. A.; Ahn, J. -W.; Bell, R. E. Nuclear Fusion, Vol. 51, Issue 1 https://doi.org/10.1088/0029-5515/51/1/012001	journal	December 2010
Impact of carbon and tungsten as divertor materials on the scrape-off layer conditions in JET Groth, M.; Brezinsek, S.; Belo, P. Nuclear Fusion, Vol. 53, Issue 9 https://doi.org/10.1088/0029-5515/53/9/093016	journal	August 2013
Power exhaust in the snowflake divertor for L- and H-mode TCV tokamak plasmas Vijvers, W. A. J.; Canal, G. P.; Labit, B. Nuclear Fusion, Vol. 54, Issue 2 https://doi.org/10.1088/0029-5515/54/2/023009	journal	February 2014
Enhanced $\boldsymbol{\vec{{E}}\times \vec{{B}}}$ drift effects in the TCV snowflake divertor Canal, G. P.; Lunt, T.; Reimerdes, H. Nuclear Fusion, Vol. 55, Issue 12 https://doi.org/10.1088/0029-5515/55/12/123023	journal	November 2015
The ‘churning mode’ of plasma convection in the tokamak divertor region Ryutov, D. D.; Cohen, R. H.; Farmer, W. A. Physica Scripta, Vol. 89, Issue 8 https://doi.org/10.1088/0031-8949/89/8/088002	journal	July 2014
Snowflake divertor plasmas on TCV Piras, F.; Coda, S.; Furno, I. Plasma Physics and Controlled Fusion, Vol. 51, Issue 5 https://doi.org/10.1088/0741-3335/51/5/055009	journal	March 2009
A snowflake divertor: a possible solution to the power exhaust problem for tokamaks Ryutov, D. D.; Cohen, R. H.; Rognlien, T. D. Plasma Physics and Controlled Fusion, Vol. 54, Issue 12 https://doi.org/10.1088/0741-3335/54/12/124050	journal	November 2012
Power distribution in the snowflake divertor in TCV Reimerdes, H.; Canal, G. P.; Duval, B. P. Plasma Physics and Controlled Fusion, Vol. 55, Issue 12 https://doi.org/10.1088/0741-3335/55/12/124027	journal	November 2013
First EMC3-Eirene simulations of the TCV snowflake divertor Lunt, T.; Canal, G. P.; Feng, Y. Plasma Physics and Controlled Fusion, Vol. 56, Issue 3 https://doi.org/10.1088/0741-3335/56/3/035009	journal	February 2014
Numerical study of potential heat flux mitigation effects in the TCV snowflake divertor Lunt, T.; Canal, G. P.; Duval, B. P. Plasma Physics and Controlled Fusion, Vol. 58, Issue 4 https://doi.org/10.1088/0741-3335/58/4/045027	journal	March 2016
Using SOLPS to confirm the importance of total flux expansion in Super-X divertors Moulton, D.; Harrison, J.; Lipschultz, B. Plasma Physics and Controlled Fusion, Vol. 59, Issue 6 https://doi.org/10.1088/1361-6587/aa6b13	journal	May 2017
SOLPS simulations of detachment in a snowflake configuration for the future upper divertor in ASDEX Upgrade Pan, O.; Lunt, T.; Wischmeier, M. Plasma Physics and Controlled Fusion, Vol. 60, Issue 8 https://doi.org/10.1088/1361-6587/aac706	journal	June 2018
SOLPS-ITER modeling with activated drifts for a snowflake divertor in ASDEX Upgrade Pan, O.; Lunt, T.; Wischmeier, M. Plasma Physics and Controlled Fusion, Vol. 62, Issue 4 https://doi.org/10.1088/1361-6587/ab7108	journal	February 2020
Overview of recent physics results from MAST Kirk, A.; Adamek, J.; Akers, R. J. Nuclear Fusion, Vol. 57, Issue 10 https://doi.org/10.1088/1741-4326/aa65e0	journal	June 2017
Developing physics basis for the snowflake divertor in the DIII-D tokamak Soukhanovskii, V. A.; Allen, S. L.; Fenstermacher, M. E. Nuclear Fusion, Vol. 58, Issue 3 https://doi.org/10.1088/1741-4326/aaa6de	journal	February 2018
Overview of new MAST physics in anticipation of first results from MAST Upgrade Harrison, J. R.; Akers, R. J.; Allan, S. Y. Nuclear Fusion, Vol. 59, Issue 11 https://doi.org/10.1088/1741-4326/ab121c	journal	June 2019
“Snowflake” H Mode in a Tokamak Plasma Piras, F.; Coda, S.; Duval, B. P. Physical Review Letters, Vol. 105, Issue 15 https://doi.org/10.1103/PHYSREVLETT.105.155003	journal	October 2010

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