The simulation of ELM control by the advanced divertor configuration in EAST
Edge localized modes (ELMs) are effectively suppressed in the ‘quasi-snowflake’ (QSF) divertor discharges, which has been observed in the Experimental Advanced Superconducting Tokamak (EAST). To obtain the physical mechanism of ELM suppression, the numerical simulations are carried out using the BOU...
Saved in:
| Main Authors: | , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | Nuclear Fusion |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1741-4326/ada1e2 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1841558338793373696 |
|---|---|
| author | Y.L. Li T.Y. Xia Z.P. Luo Q.Z. Yu S.F. Mao B. Gui X.X. He H.M. Qi P.C. Xie M.Y. Ye the EAST team |
| author_facet | Y.L. Li T.Y. Xia Z.P. Luo Q.Z. Yu S.F. Mao B. Gui X.X. He H.M. Qi P.C. Xie M.Y. Ye the EAST team |
| author_sort | Y.L. Li |
| collection | DOAJ |
| description | Edge localized modes (ELMs) are effectively suppressed in the ‘quasi-snowflake’ (QSF) divertor discharges, which has been observed in the Experimental Advanced Superconducting Tokamak (EAST). To obtain the physical mechanism of ELM suppression, the numerical simulations are carried out using the BOUT++ turbulence model. The simulations reveal that the large local magnetic shear near the outer mid-plane (OMP) induced by QSF divertor plays a key role in the ELM suppression. Using the EFIT code, a series of plasma equilibria with different 2nd X-points and nearly fixed last closed flux surfaces (LCFSs) are generated to analyze the effects of the different magnetic configurations on ELMs. Here we mainly discuss the standard single-null (SN), snowflake plus (SF+), and snowflake minus (SF-) divertors. The simulation results indicate that: (1) for linear instability, compared to SN, SF+ is more unstable, while SF- is more stable. Essentially, the local magnetic shear formed by different divertor geometries can alter the growth rate of the peeling-ballooning (P-B) mode. Through statistical analysis, there is an inverse correlation between the strength of local magnetic shear and the growth rate of P-B mode; (2) for ELM energy loss, SN is 4.60%, SF+ is 7.50%, and SF- is 0.35%. The SF+ divertor triggers a larger ELM, which is consistent with the TCV experiments; while the SF- divertor reduces the ELM amplitude, which is similar to the QSF experiments in EAST. Further analysis shows that the Reynolds stress determines the ELM size under different divertor configurations. The Reynolds stress can redistribute energy to fluctuations and cause the growth of low- n modes. What’s more, the SF- divertor not only suppresses the radial transport, but also has large magnetic flux expansion and connection length, which can reduce the target heat flux effectively. The conclusion of this paper shows that the advanced divertor configurations are promising for the future fusion. |
| format | Article |
| id | doaj-art-ac97da72b6374c1c8c09f38a999ef436 |
| institution | Kabale University |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Nuclear Fusion |
| spelling | doaj-art-ac97da72b6374c1c8c09f38a999ef4362025-01-06T09:07:23ZengIOP PublishingNuclear Fusion0029-55152025-01-0165202602710.1088/1741-4326/ada1e2The simulation of ELM control by the advanced divertor configuration in EASTY.L. Li0https://orcid.org/0000-0002-3607-7654T.Y. Xia1Z.P. Luo2https://orcid.org/0000-0002-9560-6720Q.Z. Yu3https://orcid.org/0000-0001-8135-5847S.F. Mao4https://orcid.org/0000-0002-2370-1585B. Gui5X.X. He6H.M. Qi7P.C. Xie8https://orcid.org/0000-0002-0567-646XM.Y. Ye9https://orcid.org/0000-0002-9055-1476the EAST team10Institute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaCenter for Ultimate Energy, ShanghaiTech University , Shanghai 201210, ChinaSchool of Nuclear Science and Technology, University of Science and Technology of China , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, China; School of Nuclear Science and Technology, University of Science and Technology of China , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, China; School of Nuclear Science and Technology, University of Science and Technology of China , Hefei, ChinaSchool of Nuclear Science and Technology, University of Science and Technology of China , Hefei, ChinaInstitute of Plasma Physics, Chinese Academy of Sciences , Hefei, ChinaEdge localized modes (ELMs) are effectively suppressed in the ‘quasi-snowflake’ (QSF) divertor discharges, which has been observed in the Experimental Advanced Superconducting Tokamak (EAST). To obtain the physical mechanism of ELM suppression, the numerical simulations are carried out using the BOUT++ turbulence model. The simulations reveal that the large local magnetic shear near the outer mid-plane (OMP) induced by QSF divertor plays a key role in the ELM suppression. Using the EFIT code, a series of plasma equilibria with different 2nd X-points and nearly fixed last closed flux surfaces (LCFSs) are generated to analyze the effects of the different magnetic configurations on ELMs. Here we mainly discuss the standard single-null (SN), snowflake plus (SF+), and snowflake minus (SF-) divertors. The simulation results indicate that: (1) for linear instability, compared to SN, SF+ is more unstable, while SF- is more stable. Essentially, the local magnetic shear formed by different divertor geometries can alter the growth rate of the peeling-ballooning (P-B) mode. Through statistical analysis, there is an inverse correlation between the strength of local magnetic shear and the growth rate of P-B mode; (2) for ELM energy loss, SN is 4.60%, SF+ is 7.50%, and SF- is 0.35%. The SF+ divertor triggers a larger ELM, which is consistent with the TCV experiments; while the SF- divertor reduces the ELM amplitude, which is similar to the QSF experiments in EAST. Further analysis shows that the Reynolds stress determines the ELM size under different divertor configurations. The Reynolds stress can redistribute energy to fluctuations and cause the growth of low- n modes. What’s more, the SF- divertor not only suppresses the radial transport, but also has large magnetic flux expansion and connection length, which can reduce the target heat flux effectively. The conclusion of this paper shows that the advanced divertor configurations are promising for the future fusion.https://doi.org/10.1088/1741-4326/ada1e2ELM suppressionQSF divertormagnetic configurationslocal magnetic shearthe Reynolds stressmagnetic flux expansion |
| spellingShingle | Y.L. Li T.Y. Xia Z.P. Luo Q.Z. Yu S.F. Mao B. Gui X.X. He H.M. Qi P.C. Xie M.Y. Ye the EAST team The simulation of ELM control by the advanced divertor configuration in EAST Nuclear Fusion ELM suppression QSF divertor magnetic configurations local magnetic shear the Reynolds stress magnetic flux expansion |
| title | The simulation of ELM control by the advanced divertor configuration in EAST |
| title_full | The simulation of ELM control by the advanced divertor configuration in EAST |
| title_fullStr | The simulation of ELM control by the advanced divertor configuration in EAST |
| title_full_unstemmed | The simulation of ELM control by the advanced divertor configuration in EAST |
| title_short | The simulation of ELM control by the advanced divertor configuration in EAST |
| title_sort | simulation of elm control by the advanced divertor configuration in east |
| topic | ELM suppression QSF divertor magnetic configurations local magnetic shear the Reynolds stress magnetic flux expansion |
| url | https://doi.org/10.1088/1741-4326/ada1e2 |
| work_keys_str_mv | AT ylli thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT tyxia thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT zpluo thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT qzyu thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT sfmao thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT bgui thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT xxhe thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT hmqi thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT pcxie thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT myye thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT theeastteam thesimulationofelmcontrolbytheadvanceddivertorconfigurationineast AT ylli simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT tyxia simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT zpluo simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT qzyu simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT sfmao simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT bgui simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT xxhe simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT hmqi simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT pcxie simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT myye simulationofelmcontrolbytheadvanceddivertorconfigurationineast AT theeastteam simulationofelmcontrolbytheadvanceddivertorconfigurationineast |