International Joint Research Laboratory of Magnetic Confinement Fusion
磁约束聚变与等离子体国际联合实验室 International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics Preliminary research on the island divertor configuration by applying 3/1 RMP in J-TEXT Nengchao Wang, Y. Liang, X L Zhang, J Yang Z Huang, S Zhou, J C Li, Z B Song, D Li, R H Tong, L Z Liu Huazhong University of Science and Technology 2018. 3. 27 e-mail : wangnc@hust. edu. cn
0. Background: Island Divertor Resonant Helical Divertor: Utilizing small current to generate divertor configuration l Large L|| Heat flux reduction l impurity screening l heat and particle exhaust W 7 -AS Karger, PLA 1977 2/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Content 0. Background 1. J-TEXT and its RMP systems 2. Excitation of edge islands 3. Parameter dependence of forming edge island 4. New coils for island divertor configuration on JTEXT 5. Summary and Plan 3/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Content 0. Background 1. J-TEXT and its RMP systems 1 -1. J-TEXT tokamak 1 -2. RMP coils on J-TEXT 1 -3. Scenario for generating an edge island 2. Excitation of edge islands 3. Parameter dependence of forming edge island 4. New coils for island divertor configuration on JTEXT 5. Summary and Plan 3/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
1 -0. HUST & IFPP l HUST (Huazhong University of Science and Technology) is one of the top 10 Chinese universities located in Wuhan. l IFPP (International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics) ─ Operating the J-TEXT tokamak ─ Physicists: 28 ─ Engineers: 13 ─ Students: 104 4/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
1 -1. J-TEXT tokamak Main parameters Ohmic plasma in limiter conf. R = 1. 05 m, a = 0. 255 m (limiter) Ip < 220 k. A, BT = 1. 2 ~ 2. 2 T ne = 1~5 x 1019 m-3 Te 0 ~ 1 ke. V, Ti 0 ~ 0. 5 ke. V Edge parameters Tea = 30~10 e. V, Tia = 90~20 e. V, nea ~ 0. 1 -0. 3 x 1019 m-3 • Two RMP system • Two MGI system • SPI • Biased electrode 5/25 • ECRH (under developing) • Poloidal divertor with HFSx points (under developing) Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
1 -2. RMP systems on J-TEXT 2012: 4 columns x 3 rows x 1 turn Two sets of RMP coils: l SRMP (static RMP) l DRMP (Dynamic RMP): 2017: add 4 columns x 3 rows x 2 turns 6/25 Ø In-vessel; Ø 12 coils (2012) + 12 coils (2017); Ø DC or AC (1 – 6 k. Hz) Ø Maximum current: 6 k. A Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
1 -2. RMP systems on J-TEXT - Amplitude 2/1 dominant mode 2. 63 Gs/k numbers A 2/1 6. 31 Gs/k. A 2/1 1. 83 Gs/k. A Enhanced 3/1 1. 17 Gs/k. A 1/1 4. 02 Gs/k. A 3/1 7/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 3/1 2. 95 Gs/k. A
1 -3. Scenario for generating an edge island l Larger 3/1 RMP than 4/1 RMP qa >~ 3 with RMP coils in 3/1 configuration was selected. Coils arrangement and distribution of perturbed radial magnetic field ò 3/1 island formed just inside the LCFS. dominant 3/1 and 1/1, very small 2/1 RMP. 8/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Content 0. Background 1. J-TEXT and its RMP systems 2. Excitation of edge islands 2 -1. Edge island induced via 3/1 RMP penetration 2 -2 ~ 2 -5. Features of the 3/1 island formation 3. Parameter dependence of forming edge island 4. New coils for island divertor configuration on JTEXT 5. Summary and Plan 9/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -1. Edge island induced via 3/1 RMP penetration l 3/1 RMP: w/o RMP l qa ~ 3. 3 Plasma Current RMP coil current outwards shift Horizontal position core ne ~1. 5 *1019 m-3 Vf, LFS limiter Grounding current LFS limiter dx = 1 cm CIII intensity, LFS, Φ = 90 o CIII intensity, HFS, Φ = 247. 5 o 10/25 Toroidal Rotation Ha, LFS Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -1. Edge island induced via 3/1 RMP penetration l 3/1 RMP: 2 k. A l Small change @ edge parameters Plasma Current RMP coil current Horizontal position CIII intensity, LFS, Φ = 90 o CIII intensity, HFS, Φ = 247. 5 o 10/25 core ne Vf, LFS limiter Grounding current LFS limiter Toroidal Rotation Ha, LFS Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -1. Edge island induced via 3/1 RMP penetration l 3/1 RMP: 4 k. A l Clear change in the edge structures Plasma Current RMP coil current Horizontal position CIII intensity, LFS, Φ = 90 o CIII intensity, HFS, Φ = 247. 5 o 10/25 core ne Vf, LFS limiter Grounding current LFS limiter Toroidal Rotation Ha, LFS Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Ch 18 2 -2. Impurities: CIII & Ha Ha & CIII LFS, φ = 90 o The impurity radiation are measured at several locations. 11/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Ch 18 2 -2. Impurities: CIII & Ha Ha & CIII LFS, φ = 90 o After 3/1 RMP applied: CIII intensity increased a little (near LFCS) Ha intensity increased ~ 10 % 11/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Ch 18 2 -2. Impurities: CIII & Ha Ha & CIII LFS, φ = 90 o After 3/1 RMP penetration : CIII intensity increased ~ 30%, Ha intensity increased ~ 25 % 11/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -3. Excitation of BAE RMP 2 k. A vs 4 k. A of dbθ/dt BAE was excited together with 3/1 island excitation 12/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -4. Vf at the limiters l LFS limiter act as the main limiter. l In Reference discharge, Vf(s, t) were kept constant. θ 13/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -4. Vf at the limiters l 2 k. A l Interaction between the top limiter and the plasma are modified. θ 13/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -4. Vf at the limiters l 4 k. A, with 3/1 island l Significant modification on the LFS limiter. θ 13/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -5. Vf(r) and Er change l With the 3/1 island, Vf(r) and Er(r) increased / inward shifted. 14/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
2 -6. Brief summary on 3/1 island excitation l The penetration of 3/1 RMP are involved in these tokamak plasmas with qa >~3. l Features of the 3/1 RMP penetration: Ø acceleration in co-Ip direction (vi*) Ø increase the impurity content Ø change of the floating potential and Er Ø excitation of BAE mode Ø Increase of ne (Hu Q, NF 56 (2016) 092009) Shift the 3/1 island towards LCFS Parameter dependence ─ island phase; RMP frequency; density; 15/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Content 0. Background 1. J-TEXT and its RMP systems 2. Excitation of edge islands 3. Parameter dependence of forming edge island ─ qa, RMP phase, frequency, density 4. New coils for island divertor configuration on JTEXT 5. Summary and Plan 16/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
3 -1. qa ramp-down island divertor/limiter l Ip qa shift r 3/1 outwards. 3. 4 3. 1 l 3/1 island excited at qa ~ 3. 15 (IRMP = 2 k. A) θ = 30 o 17/25 θ = 0 o Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
3 -1. qa ramp-down island divertor/limiter l Ip qa shift r 3/1 outwards. 3. 4 3. 1 l 3/1 island excited early with (IRMP = 3 k. A) l Island phase shifted during qa ? Larger I CIII node of the standing wave (BAE) θ = 30 o 17/25 θ = 0 o Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
3 -1. qa ramp-down island divertor/limiter l Ip qa shift r 3/1 outwards. 3. 4 3. 1 l BAE exist, 3/1 RS still inside the LCFS. l Further qa is still needed. node of the standing wave (BAE) θ = 30 o 17/25 θ = 0 o Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
3 -2. RMP phase dependence 3. 4 #253 θ = 0 o 18/25 2. 45 θ = 30 o Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 Phase of 3/1 RMP
3 -2. RMP phase dependence 3. 4 #253 θ = 0 o 2. 45 θ = 30 o #254 18/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 Phase of 3/1 RMP
3 -2. RMP phase dependence 3. 4 #253 θ = 0 o 2. 45 θ = 30 o #254 18/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 Phase of 3/1 RMP #255
3 -2. RMP phase dependence #191 #253 θ = 0 o 2. 45 θ = 30 o #254 18/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 3. 4 Phase of 3/1 RMP #255
3 -3. High frequency RMPs l 3/1 RMP rotating at 5. 3 k. Hz penetrated and excited a rotating 3/1 island near the edge. Good for: Measure the impact of island phase on: (1) parameter profiles, (2) turbulence (3) screening currents & island radial location 19/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
3 -4. Density dependence 2/1 locked island excited following the 3/1 island at low n e ne = 1. 1:core response 4 columns x 1 turn (1/1), linear to IRMP & fixed phase ne = 0. 95: 3/1 locked island excited ne = 0. 8: 2/1 locked island excited 4 columns, 1 turn 20/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018 n=1
3 -4. Density dependence Thresholds for 3/1 or 2/1 island excitation. p Hypothesis excitation large 3/1 island for 2/1 low ne toroidal coupling large 2/1 RMP 4 columns x 1 turn Hu Q, NF 56 (2016) 092009 low threshold for exciting 2/1 locked mode error field, small 2/1 RMP from RMP coils 2/1 locked island p No large 2/1 locked island To avoid the 2/1 island is of excited when neave>1. 1 great importance! 21/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Content 0. Background 1. J-TEXT and its RMP systems 2. Excitation of edge islands 3. Parameter dependence of forming edge island 4. New coils for island divertor configuration on JTEXT 5. Summary and Plan 22/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
4 -1. New coils for J-TEXT island divertor l Essential aspects Ø Avoid 2/1 excitation Ø Island width as large as possible higher ne, 4/1 island S-type modular coils Gauss/k. A Pumping Target - - m 23/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
5. Summary and Plan l Steady edge island has been formed by the application of 3/1 RMP on J-TEXT. l The edge island influenced the ICIII, Vtor, Vf (linked to the footprints). l Measure the heat load on the targets; the edge profiles of Te, ne, Mach number, turbulence, perturbed currents, etc. l New ID coils and divertor components; l Property at various ne. 24/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Thank you very much! Comments are welcome! 25/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
38/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
4 -2. Helical coils VS Helical current filaments l Helical SOL current filament driven by biased electrode could influence the edge topology CIII Karger, PLA 1977 fast camera Could it be the island divertor coils? 39/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
qa ramp-down #204, 4 k. A #203, 3 k. A #206, 2 k. A #205, 0 k. A 40/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
qa ramp-down 2 k. A, w/o BAE IRMP Linear Penetration 3 k. A, BAE 0. 42 -0. 46 s 0. 49 -0. 53 s 4 k. A, BAE 0. 30 -0. 54 s The increase of magnetic response (brn=1) corresponding to the appearance of BAE. 41/25 Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
Plasma Response @ various toroidal phase 3/1 Rough Estimation on the phase of 3/1 RMP, ξ #191, #249 #250 #253 Red: IDC(1, 2) = (1, -1) 3. 4 2. 8 P 14 2 2. 45 Measured plasma response #256, 257 1. 4 -137 o -130 o -112 o -160 o 40 o 65 o 20 o 35 o P 1 φn=1 P 12 3/1 island? #255 #258 #254 42/25 Blue: IDC(1, 2) = (-1, 1) Nengchao Wang | Island Divertor on J-TEXT | HISW, Mar. 26 -28, 2018
- Slides: 42