Understanding L–H transition in tokamak fusion plasmas

Guosheng XU (徐国盛); Xingquan WU (伍兴权)

doi:10.1088/2058-6272/19/3/033001

Plasma Science and Technology > 2017 > 19(3): 33001-033001. > DOI: 10.1088/2058-6272/19/3/033001

Guosheng XU (徐国盛), Xingquan WU (伍兴权). Understanding L–H transition in tokamak fusion plasmas[J]. Plasma Science and Technology, 2017, 19(3): 33001-033001. DOI: 10.1088/2058-6272/19/3/033001

Citation:

PDF (1906 KB)

Understanding L–H transition in tokamak fusion plasmas

Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People’s Republic of China

Funds: This work was supported by National Magnetic Confinement Fusion Science Program of China under Contracts No. 2015GB101000, No. 2013GB106000, and No. 2013GB107000 and National Natural Science Foundation of China under Contracts No. 11575235 and No. 11422546.

More Information

Received Date: May 05, 2016

Graphical Abstract

Abstract

Abstract

This paper reviews the current state of understanding of the L–H transition phenomenon in tokamak plasmas with a focus on two central issues: (a) the mechanism for turbulence quick suppression at the L–H transition; (b) the mechanism for subsequent generation of sheared flow. We briefly review recent advances in the understanding of the fast suppression of edge turbulence across the L–H transition. We uncover a comprehensive physical picture of the L–H transition by piecing together a number of recent experimental observations and insights obtained from 1D and 2D simulation models. Different roles played by diamagnetic mean flow, neoclassical-driven mean flow, turbulence-driven mean flow, and turbulence-driven zonal flows are discussed and clarified. It is found that the L–H transition occurs spontaneously mediated by a shift in the radial wavenumber spectrum of edge turbulence, which provides a critical evidence for the theory of turbulence quench by the flow shear. Remaining questions and some key directions for future investigations are proposed.
- L–H transition,
- E×B flow shear,
- turbulence suppression,
- zonal flows,
- Reynolds stress

FullText(HTML)

References (61)

References

[1]	Moyer R A et al 1995 Phys. Plasmas 2 2397
[2]	Burrell K H 1997 Phys. Plasmas 4 1499
[3]	Wagner F et al 1982 Phys. Rev. Lett. 49 1408
[4]	Shimada M et al 2007 Nucl. Fusion 47 S1
[5]	Stringer T E 1969 Phys. Rev. Lett. 22 770
[6]	Itoh K 1994 Plasma Phys. Control. Fusion 36 A307
[7]	Itoh S I and Itoh K 1988 Phys. Rev. Lett. 60 2276
[8]	Shaing K C and Crume E C 1989 Phys. Rev. Lett. 63 2369
[9]	Biglari H, Diamond P H and Terry P W 1990 Phys. Fluids B 2 1
[10]	Hinton F L and Staebler G M 1993 Phys. Fluids B 5 1281
[11]	Zhang Y Z and Mahajan S M 1992 Phys. Fluids B 4 1385
[12]	Diamond P H et al 2005 Plasma Phys. Control. Fusion 47 R35
[13]	Kim E J and Diamond P H 2003 Phys. Rev. Lett. 90 185006
[14]	Diamond P H et al 1994 Phys. Rev. Lett. 72 2565
[15]	Staebler G M et al 2013 Phys. Rev. Lett. 110 055003
[16]	Staebler G M et al 2013 Nucl. Fusion 53 113017
[17]	Waltz R E, Dewar R L and Garbet X 1998 Phys. Plasmas 5 1784
[18]	Connor J W and Wilson H R 2000 Plasma Phys. Control.Fusion 42 R1
[19]	Bishop C M 1986 Nucl. Fusion 26 1063
[20]	Rogers B N, Drake J F and Zeiler A 1998 Phys. Rev. Lett.81 4396
[21]	Terry P W 2000 Rev. Mod. Phys. 72 109
[22]	Kim J et al 1994 Plasma Phys. Control. Fusion 36 A183
[23]	Viezzer E et al 2014 Nucl. Fusion 54 012003
[24]	Fujisawa A 2009 Nucl. Fusion 49 013001
[25]	Hillesheim J C et al 2016 Phys. Rev. Lett. 116 065002
[26]	Sauter P et al 2012 Nucl. Fusion 52 012001
[27]	Shao L M et al 2016 Plasma Phys. Control. Fusion 58 025004
[28]	Hirshman S P and Sigmar D J 1981 Nucl. Fusion 21 1079
[29]	Callen J D, Cole A J and Hegna C C 2009 Nucl. Fusion 49 085021
[30]	Wu X Q et al 2015 Nucl. Fusion 55 053029
[31]	Diamond P H and Kim Y B 1991 Phys. Fluids B 3 1626
[32]	Morris R C, Haines M G and Hastie R J 1996 Phys. Plasmas 3 4513
[33]	McDevitt C J et al 2010 Phys. Plasmas 17 112509
[34]	Rozhansky V and Tendler M 1992 Phys. Fluids B 4 1877
[35]	Rozhansky V A et al 2001 Nucl. Fusion 41 387
[36]	Xu G S et al 2014 Nucl. Fusion 54 103002
[37]	Pitcher C S and Stangeby P C 1997 Plasma Phys. Control.Fusion 39 779
[38]	LaBombard B et al 2004 Nucl. Fusion 44 1047
[39]	Kim J et al 1994 Phys. Rev. Lett. 72 2199
[40]	Xu G S et al 2011 Phys. Rev. Lett. 107 125001
[41]	Muller S H et al 2014 Phys. Plasmas 21 042301
[42]	Cheng J et al 2013 Phys. Rev. Lett. 110 265002
[43]	Xu G S et al 2009 Nucl. Fusion 49 092002
[44]	Manz P et al 2012 Phys. Plasmas 19 072311
[45]	Tynan G R et al 2013 Nucl. Fusion 53 073053
[46]	Yan Z et al 2014 Phys. Rev. Lett. 112 125002
[47]	Cziegler I et al 2014 Plasma Phys. Control. Fusion 56 075013
[48]	Xu G S et al 2014 Nucl. Fusion 54 013007
[49]	Shao L M et al 2013 Plasma Phys. Control. Fusion 55 105006
[50]	Nielsen A H et al 2015 Phys. Lett. A 379 3097
[51]	Rasmussen J J et al 2016 Plasma Phys. Control. Fusion 58 014031
[52]	Xu X Q et al 2000 Phys. Plasmas 7 1951
[53]	Xia T Y, Xu X Q and Xi P W 2013 Nucl. Fusion 53 073009
[54]	Li B et al 2015 Phys. Plasmas 22 112304
[55]	Waltz R E et al 1995 Phys. Plasmas 2 2408
[56]	Waltz R E, Kerbel G D and Milovich J 1994 Phys. Plasmas 1 2229
[57]	Doyle E J et al 1991 Phys. Fluids B 3 2300
[58]	Xu G S et al 2016 Phys. Rev. Lett. 116 095002
[59]	Frieman E A and Chen L 1982 Phys. Fluids 25 502
[60]	Staebler G M and Groebner R J 2015 Plasma Phys. Control.Fusion 57 014025
[61]	Staebler G M and Groebner R J 2015 Nucl. Fusion 55 073008

[1]	Wenjia WANG (王文家), Deng ZHOU (周登), Yue MING (明玥). The residual zonal flow in tokamak plasmas with a poloidal electric field[J]. Plasma Science and Technology, 2019, 21(1): 15101-015101. DOI: 10.1088/2058-6272/aadd8e
[2]	K J ZHAO (赵开君), J Q DONG (董家齐), J Q LI (李继全), LW YAN (严龙文). A brief review: experimental investigation of zonal flows and geodesic acoustic modes in fusion plasmas[J]. Plasma Science and Technology, 2018, 20(9): 94006-094006. DOI: 10.1088/2058-6272/aad382
[3]	Xingquan WU (伍兴权), Guosheng XU (徐国盛), Baonian WAN (万宝年), Jens Juul RASMUSSEN, Volker NAULIN, Anders Henry NIELSEN, Liang CHEN (陈良), Ran CHEN (陈冉), Ning YAN (颜宁), Linming SHAO (邵林明). A new model of the L–H transition and H-mode power threshold[J]. Plasma Science and Technology, 2018, 20(9): 94003-094003. DOI: 10.1088/2058-6272/aabb9e
[4]	Jan WEILAND. The role of zonal flows in reactive fluid closures[J]. Plasma Science and Technology, 2018, 20(7): 74007-074007. DOI: 10.1088/2058-6272/aab20d
[5]	Jinkui FENG (冯金奎), Decheng WANG (王德成), Changyong SHAO (邵长勇), Lili ZHANG (张丽丽), Xin TANG (唐欣). Effects of cold plasma treatment on alfalfa seed growth under simulated drought stress[J]. Plasma Science and Technology, 2018, 20(3): 35505-035505. DOI: 10.1088/2058-6272/aa9b27
[6]	Wulyu ZHONG (钟武律), Xiaolan ZOU (邹晓岚), Zhongbing SHI (石中兵), Xuru DUAN (段旭如), Min XU (许敏), Zengchen YANG (杨曾辰), Peiwan SHI (施培万), Min JIANG (蒋敏), Guoliang XIAO (肖国梁), Xianming SONG (宋显明), Jiaqi DONG (董家齐), Xuantong DING (丁玄同), Yong LIU (刘永), HL-A team (HL-A团队). Dynamics of oscillatory plasma flows prior to the H-mode in the HL-2A tokamak[J]. Plasma Science and Technology, 2017, 19(7): 70501-070501. DOI: 10.1088/2058-6272/aa6538
[7]	Hailin ZHAO (赵海林), Tao LAN (兰涛), Adi LIU (刘阿娣), Defeng KONG (孔德峰), Huagang SHEN (沈华刚), Jie WU (吴捷), Wandong LIU (刘万东), Changxuan YU (俞昌旋), Wei ZHANG (张炜), Guosheng XU (徐国盛), Baonian WAN (万宝年). Zonal flow energy ratio evolution during L-H and H-L transitions in EAST plasmas[J]. Plasma Science and Technology, 2017, 19(3): 35101-035101. DOI: 10.1088/2058-6272/19/3/035101
[8]	CEN Yishun (岑义顺), LI Qiang (李强), DING Yonghua (丁永华), CAI Lijun (蔡立君), et al.. Stress and Thermal Analysis of the In-Vessel RMP Coils in HL-2M[J]. Plasma Science and Technology, 2013, 15(9): 939-944. DOI: 10.1088/1009-0630/15/9/20
[9]	ZHU Dahuan (朱大焕), WANG Kun (王坤), WANG Xianping (王先平), CHEN Junling (陈俊凌), FANG Qianfeng (方前锋). Analysis of residual thermal stress in CVD-W coating as plasma facing material[J]. Plasma Science and Technology, 2012, 14(7): 656-660. DOI: 10.1088/1009-0630/14/7/20
[10]	T. WATARI, Y. HAMADA. Linear Gyro-Kinetic Response Function for Zonal Flows[J]. Plasma Science and Technology, 2011, 13(2): 157-161.