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基于HL-2A实验参数, 利用TOQ程序构建了具有不同台基结构的平衡, 在BOUT++三场模块下对台基磁流体力学(magnetohydrodynamics, MHD)稳定性进行数值模拟研究. 线性模拟表明, 减小台基高度、增大台基宽度、减小台基电流能够提高台基MHD稳定性, 利用色散关系理论, 对上述现象进行解释. 在MHD稳定性的前提下, 预测了不同台基宽度对应的最高台基高度, 对数据进行拟合, 得到可以预测临界台基高度的公式, 并在此基础上结合动理学气球模(kinetic ballooning mode, KBM)理论, 同时预测了台基高度和宽度. 本文也研究了台基结构对MHD不稳定模式的影响, 线性模拟表明, 台基高度能够微弱影响不稳定模式的径向模展宽; 非线性模拟表明, 不稳定模式的前期增长主要受单一主导模的影响, 模式增长到一定大小会发生台基坍塌, 爆发边缘局域模(edge localized mode, ELM), ELM尺寸的演化与主导模幅值的演化同步, 总体来说具有较大线性增长率的平衡在非线性模拟中具有更大的ELM尺寸和更广范围的台基坍塌.HL-2A tokamak achieved the first ELMy H-mode discharge operation in 2009 under divertor configuration, and many experimental and simulation researches have been carried out to investigate the pedestal magnetohydrodynamic (MHD) instability. However, there are still few studies on the effect of pedestal structure on MHD stability. Therefore, based on HL-2A experimental parameters, equilibria with different pedestal structures are generated by using TOQ code, and the MHD stability of the equilibria is simulated by using the BOUT++ three-field module. The linear simulations show that reducing the pedestal height, increasing the pedestal width, reducing the pedestal current density and reducing the ion density in the pedestal can improve the MHD stability of pedestal. Using the theory of dispersion relation, the simulation results are explained. Under the premise of MHD stability, the maximum pedestal heights corresponding to different pedestal widths are found, and the data are fitted to obtain an empirical formula that can predict pedestal height, and on this basis, considering the kinetic ballooning mode theory, pedestal height and width are predicted simultaneously. The effect of the pedestal structure on the MHD mode structure is investigated, it is found that the pedestal height can affect the radial width of the mode. Nonlinear simulations show that the pre-growth of instability is affected mainly by a single dominant mode, and the growth of the dominant mode to a certain size will cause the collapse of the pedestal and the eruption of the edge localized mode (ELM). The variation of ELM size after ELM eruption is synchronized with the evolution of the dominant mode. Generally, equilibria with larger linear growth rates have larger ELM sizes and a wider range of pedestal collapse in nonlinear simulations. In this work, the scanning of the pedestal data focuses mainly on the width and height of the pedestal, and other parameters such as small radius, toroidal magnetic field, plasma current, and the pedestal safety factor values will be changed in the future based on the work in this paper, with the aim of enriching the HL-2A pedestal database and predicting the pedestal structure more accurately. Finally these results will be integrated under the HL-2A integrated platform, which in turn will provide a reference for HL-2A tokamak H-mode experiments and integrated simulations.
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Keywords:
- HL-2A /
- pedestal height /
- pedestal width /
- MHD stability /
- ELM
[1] ITER Physics Expert Group on Confinement and Transport, ITER Physics Expert Group on Confinement Modelling and Database, ITER Physics Basis Editors 1999 Nucl. Fusion 39 2175Google Scholar
[2] Aymar R, Barabaschi P, Shimomura Y 2002 Plasma Phys. Control. Fusion 44 519Google Scholar
[3] Neuhauser J, Alexander M, Becker G, et al. 1995 Plasma Phys. Control. Fusion 37 A37Google Scholar
[4] Groebner R J, Osborne T H 1998 Phys. Plasmas 5 1800Google Scholar
[5] Connor J W, Hastie R J, Wilson H R, Miller R L 1998 Phys. Plasmas 5 2687Google Scholar
[6] Wu N, Chen S Y, Mou M L, Tang C J 2018 Phys. Plasmas 25 092305Google Scholar
[7] Sun C K, Xu X Q, Ma C H, Li B 2018 Phys. Plasmas 25 082106Google Scholar
[8] Snyder P B, Wilson H R, Ferron J R, Lao L L, Leonard A W, Osborne T H, Turnbull A D, Mossessian D, Murakami M, Xu X Q 2002 Phys. Plasmas 9 2037Google Scholar
[9] Federici G, Andrew P, Barabaschi P, Brooks J, Doerner R, Geier A, Herrmann A, Janeschitz G, Krieger K, Kukushkin A, Loarte A, Neu R, Saibene G, Shimada M, Strohmayer G, Sugihara M 2003 J. Nucl. Mater. 313-316 11Google Scholar
[10] Zohm H 1996 Plasma Phys. Control. Fusion 38 105Google Scholar
[11] Snyder P B, Wilson H R, Ferron J R, Lao L L, Leonard A W, Mossessian D, Murakami M, Osborne T H, Turnbull A D, Xu X Q 2004 Nucl. Fusion 44 320Google Scholar
[12] Wilson H R, Snyder P B, Huysmans G T A, Miller R L 2002 Phys. Plasmas 9 1277Google Scholar
[13] Chance M S, Chu M S, Okabayashi M, Turnbull A D 2002 Nucl. Fusion 42 295Google Scholar
[14] Huysmans G T A, Sharapov S E, Mikhailovskii A B, Kerner W 2001 Phys. Plasmas 8 4292Google Scholar
[15] Dudson B D, Umansky M V, Xu X Q, Snyder P B, Wilson H R 2009 Comput. Phys. Commun. 180 1467Google Scholar
[16] Snyder P B, Aiba N, Beurskens M, Groebner R J, Horton L D, Hubbard A E, Hughes J W, Huysmans G T A, Kamada Y, Kirk A, Konz C, Leonard A W, Lönnroth J, Maggi C F, Maingi R, Osborne T H, Oyama N, Pankin A, Saarelma S, Saibene G, Terry J L, Urano H, Wilson H R 2009 Nucl. Fusion 49 085035Google Scholar
[17] Snyder P B, Groebner R J, Hughes J W, Osborne T H, Beurskens M, Leonard A W, Wilson H R, Xu X Q 2011 Nucl. Fusion 51 103016Google Scholar
[18] Groebner R J, Chang C S, Hughes J W, et al. 2013 Nucl. Fusion 53 093024Google Scholar
[19] 李凯 2020 博士学位论文 (合肥: 中国科学技术大学)
Li K 2020 Ph. D. Dissertation (Hefei: University of Science and Technology of China) (in Chinese)
[20] Xu X Q, Dudson B, Snyder P B, Umansky M V, Wilson H 2010 Phys. Rev. Lett. 105 175005Google Scholar
[21] Xia T Y, Xu X Q, Dudson B D, Li J 2012 Contrib. Plasma Phys. 52 353Google Scholar
[22] Xia T Y, Xu X Q 2013 Phys. Plasmas 20 052102Google Scholar
[23] Xia T Y, Xu X Q, Xi P W 2013 Nucl. Fusion 53 073009Google Scholar
[24] Xu X Q, Dudson B D, Snyder P B, Umansky M V, Wilson H R, Casper T 2011 Nucl. Fusion 51 103040Google Scholar
[25] Duan X R, Dong J Q, Yan L W, Ding X T, Yang Q W, Rao J, Liu D Q, Xuan W M, Chen L Y, Li X D, Lei G J, Cao J Y, Cao Z, Song X M, Huang Y, Liu Yi, Mao W C, Wang Q M, Cui Z Y, Ji X Q, Li B, Li G S, Li H J, Luo C W, Wang Y Q, Yao L H, Yao L Y, Zhang J H, Zhou J, Zhou Y, Liu Yong, HL-2A Team 2010 Nucl. Fusion 50 095011Google Scholar
[26] Duan X R, Liu Yi, Xu M, et al., HL-2 A Team. 2017 Nucl. Fusion 57 102013Google Scholar
[27] Xu M, Duan X R Liu Yi, Song X M, et al., HL2A Team. 2019 Nucl. Fusion 59 112017Google Scholar
[28] Xiao G L, Zhong W L, Zhang Y P, et al., HL-2A Team. 2020 J. Fusion Energy 39 300Google Scholar
[29] Tang T F, Shi H, Wang Z H, Zhong W L, Xia T Y, Xu X Q, Sun J Z, Wang D Z 2018 Phys. Plasmas 25 122510Google Scholar
[30] Wu N, Chen S Y, Mou M L Tang C J, Song X M, Yang Z C, Yu D L, Xu J Q, Jiang M, Ji X Q, Wang S, Li B, Liu L, HL-2 A Team 2018 Phys. Plasmas 25 102505Google Scholar
[31] Ma J F, Xu X Q, Dudson B D 2014 Nucl. Fusion 54 033011Google Scholar
[32] Xi P W, Xu X Q, Xia T Y, Nevins W M, Kim S S 2013 Nucl. Fusion 53 113020Google Scholar
[33] Lortz D 1975 Nucl. Fusion 15 49Google Scholar
[34] Huang Y Q, Xia T Y, Gui B 2018 Plasma Sci. Technol. 20 045101Google Scholar
[35] 简翔 2018 博士学位论文 (武汉: 华中科技大学)
Jian X 2018 Ph. D. Dissertation (Wuhan: Huazhong University of Science and Technology) (in Chinese)
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图 4 台基高度
${\beta _{\rm{t}}}$ 为$2.0\times {10}^{-3},\, 3.0\times {10}^{-3}$ 和$4.0\times {10}^{-3} $ , 台基宽度${\varDelta _\psi }$ 为0.066, 0.077, 0.088, 0.099和0.110时的压强(a) 、平行电流和安全因子(b)(c)剖面Fig. 4. Pressure (a), parallel current density and safety factor profiles (b)(c) with pedestal heights
${\beta _{\rm t}}$ of$2.0 \times {10^{ - 3}}, $ $ 3{\text{.0}} \times {10^{ - 3}}$ and$4.0 \times {10^{ - 3}}$ , and pedestal widths${\varDelta _\psi }$ of 0.066, 0.077, 0.088, 0.099 and 0.110.图 5 理想MHD线性增长率 (a) 台基高度
${\beta _{\rm t}}$ 分别为$2.0\times {10}^{-3},\, 3.0\times {10}^{-3}$ 和4.0 × 10–3, 台基宽度${\varDelta _\psi }$ = 0.110; (b) 台基高度$ {\beta _{\rm t}} = 3.0 \times {10^{ - 3}} $ , 台基宽度${\varDelta _\psi }$ 分别为0.066, 0.077, 0.088, 0.099和0.110Fig. 5. Linear growth rates with different pedestals: (a) Pedestal heights
${\beta _{\rm t}}$ are$2.0 \times {10^{ - 3}}$ ,${\text{3}}{\text{.0}} \times {10^{ - 3}}$ and$4.0 \times {10^{ - 3}}$ , while pedestal width${\varDelta _\psi }$ is 0.110; (b) pedestal height${\beta _{\rm t}}$ is${\text{3}}{\text{.0}} \times {10^{ - 3}}$ while pedestal widths${\varDelta _\psi }$ are 0.066, 0.077, 0.088, 0.099 and 0.110.图 7 (a) 台基高度
${\beta _{\rm t}}$ 分别为$3.0 \times {10^{ - 3}},\, {\text{ }}4.0 \times {10^{ - 3}}, $ $ {\text{ }}5.0 \times {10^{ - 3}}$ 和$ 6.0 \times {10^{ - 3}} $ , 台基宽度${\varDelta _\psi }$ 为 0.066,$ n = 15 $ 的归一化径向模结构; (b) 台基高度$ {\beta _{\rm t}} = 4.0 \times {10^{ - 3}} $ , 台基宽度${\varDelta _\psi }$ 分别为0.066, 0.077, 0.088和0.099,$ n = 15 $ 的归一化径向模结构; (c) 台基高度$ {\beta _{\rm t}} = 4.0 \times $ $ {10^{ - 3}} $ , 台基宽度${\varDelta _\psi }$ = 0.066,$ n = 15 $ 的归一化二维模结构Fig. 7. (a) The normalized radial mode structure of
$ n = 15 $ when pedestal heights${\beta _{\rm t}}$ are$3.0 \times {10^{ - 3}},\, 4{\text{.0}} \times {10^{ - 3}},\,5.0 \times $ $ {10^{ - 3}}$ and$6.0 \times {10^{ - 3}}$ , while pedestal width${\varDelta _\psi }$ is 0.088; (b) the normalized radial mode structure of$ n = 15 $ when pedestal height$ {\beta _{\rm t}} $ is$ 4.0 \times {10^{ - 3}} $ , pedestal widths${\varDelta _\psi }$ are 0.066, 0.077, 0.088 and 0.099 respectively; (c) the normalized two-dimensional mode structure of$ n = 15 $ when pedestal height${\beta _{\rm t}}$ is$ 4.0 \times {10^{ - 3}} $ and pedestal width${\varDelta _\psi }$ is$0.066$ 图 9 (a) 不同安全因子的条件下, 剥离-气球模(PBM)稳定性限制下的台基高度和宽度的关系, 以及动理学气球模(KBM)稳定性限制下的台基高度和宽度的关系, 两者的交点即为台基高度和宽度的预测值; (b) 剥离-气球模(PBM)稳定性约束拟合直线的斜率
$k$ 和截距$b$ 随${q_{95}}$ 的变化Fig. 9. (a) Relationship between the pedestal height and width under the stability constraints of peeling-ballooning mode (PBM), and relationship between the pedestal height and width under the stability of constraint of kinetic ballooning mode (KBM), the insterection of the two is the predicted value of pedestal height and width; (b) the slope
$k$ and intercept$b$ of the fitting lines with the stability constraints of peeling-ballooning model (PBM) vary with${q_{95}}$ .图 10 在考虑抗磁效应时, 具有不同离子密度的剥离-气球模增长率, 台基高度
${\beta _{\rm t}} = 4.0 \times {10^{ - 3}}$ , 台基宽度${\varDelta _\psi }$ = 0.066Fig. 10. When the diamagnetic drift effect is included, linear growth rates of peeling-ballooning modes with different ion densities, while pedestal height
${\beta _{\rm t} } = 4.0 \times {10^{ - 3}}$ and pedestal width${\varDelta _\psi }$ = 0.066.图 11 不同台基结构和安全因子剖面的ELM尺寸 (a) 台基高度
$ {\beta _{\rm t} } $ 分别为$ 2.0 \times {10^{ - 3}} $ 、2.5$ \times {10^{ - 3}} $ 和$ 3.0 \times {10^{ - 3}} $ , 台基宽度${\varDelta _\psi }$ 分别为0.066, 0.077和0.088, 安全因子剖面为图8(a)中的$ {q_3} $ ; (b) 台基高度${\beta _{\rm t} } = 3.0 \times {10^{ - 3}}$ , 台基宽度${\varDelta _\psi }$ = 0.088, 安全因子剖面分别为图8(a)中的$ {q_3} $ 、$ {q_4} $ 和${q_5}$ Fig. 11. ELM size corresponding to different pedestal structures and safety factor profiles: (a)
${\beta _{\rm t} }$ are$ 2.0 \times {10^{ - 3}} $ ,$ 2.5 \times {10^{ - 3}} $ and$3.0 \times {10^{ - 3}}$ ,${\varDelta _\psi }$ = 0.066, 0.077, 0.088, while safety factor profile is the${q_3}$ profile in Fig. 8(a); (b)${\beta _{\rm t} }$ is$3.0 \times {10^{ - 3}}$ ,${\varDelta _\psi }$ is$0.088$ , while safety factor profiles are the${q_3}$ ,${q_4}$ and${q_5}$ profiles in Fig. 8(a).图 12 当台基高度
${\beta _{\rm t} } = 3.0 \times {10^{ - 3}}$ , 台基宽度${\varDelta _\psi }$ = 0.088, 安全因子剖面为图8(a)中的${q_4}$ 时, 归一化的扰动压强在径向$\psi $ 和环向$\zeta $ 平面随时间的演化Fig. 12. Evolution of pressure perturbation in the frame of normalized poloidal flux
$\psi $ and toroidal angle$\zeta $ with pedestal height${\beta _{\rm t} } = 3.0 \times {10^{ - 3}}$ and pedestal width${\varDelta _\psi }$ = 0.088, while safety factor profile is the${q_4}$ profile in figure 8(a).图 17 固定台基高度
${\beta _{\rm t}} = 3.0 \times {10^{ - 3}}$ 和台基宽度${\varDelta _\psi }$ = 0.088, 当安全因子剖面不同时, 非线性模拟中$t = 195{\tau _{\rm A} }$ 时刻磁面平均的总压强分布Fig. 17. Fixed
${\beta _{\rm t}} = 3.0 \times {10^{ - 3}}$ ,${\varDelta _\psi }$ = 0.088, when safety factor profiles are different, the surface-averaged pressure profiles distribution at$t = 195{\tau _{\rm A}}$ in the nonlinear simulations. -
[1] ITER Physics Expert Group on Confinement and Transport, ITER Physics Expert Group on Confinement Modelling and Database, ITER Physics Basis Editors 1999 Nucl. Fusion 39 2175Google Scholar
[2] Aymar R, Barabaschi P, Shimomura Y 2002 Plasma Phys. Control. Fusion 44 519Google Scholar
[3] Neuhauser J, Alexander M, Becker G, et al. 1995 Plasma Phys. Control. Fusion 37 A37Google Scholar
[4] Groebner R J, Osborne T H 1998 Phys. Plasmas 5 1800Google Scholar
[5] Connor J W, Hastie R J, Wilson H R, Miller R L 1998 Phys. Plasmas 5 2687Google Scholar
[6] Wu N, Chen S Y, Mou M L, Tang C J 2018 Phys. Plasmas 25 092305Google Scholar
[7] Sun C K, Xu X Q, Ma C H, Li B 2018 Phys. Plasmas 25 082106Google Scholar
[8] Snyder P B, Wilson H R, Ferron J R, Lao L L, Leonard A W, Osborne T H, Turnbull A D, Mossessian D, Murakami M, Xu X Q 2002 Phys. Plasmas 9 2037Google Scholar
[9] Federici G, Andrew P, Barabaschi P, Brooks J, Doerner R, Geier A, Herrmann A, Janeschitz G, Krieger K, Kukushkin A, Loarte A, Neu R, Saibene G, Shimada M, Strohmayer G, Sugihara M 2003 J. Nucl. Mater. 313-316 11Google Scholar
[10] Zohm H 1996 Plasma Phys. Control. Fusion 38 105Google Scholar
[11] Snyder P B, Wilson H R, Ferron J R, Lao L L, Leonard A W, Mossessian D, Murakami M, Osborne T H, Turnbull A D, Xu X Q 2004 Nucl. Fusion 44 320Google Scholar
[12] Wilson H R, Snyder P B, Huysmans G T A, Miller R L 2002 Phys. Plasmas 9 1277Google Scholar
[13] Chance M S, Chu M S, Okabayashi M, Turnbull A D 2002 Nucl. Fusion 42 295Google Scholar
[14] Huysmans G T A, Sharapov S E, Mikhailovskii A B, Kerner W 2001 Phys. Plasmas 8 4292Google Scholar
[15] Dudson B D, Umansky M V, Xu X Q, Snyder P B, Wilson H R 2009 Comput. Phys. Commun. 180 1467Google Scholar
[16] Snyder P B, Aiba N, Beurskens M, Groebner R J, Horton L D, Hubbard A E, Hughes J W, Huysmans G T A, Kamada Y, Kirk A, Konz C, Leonard A W, Lönnroth J, Maggi C F, Maingi R, Osborne T H, Oyama N, Pankin A, Saarelma S, Saibene G, Terry J L, Urano H, Wilson H R 2009 Nucl. Fusion 49 085035Google Scholar
[17] Snyder P B, Groebner R J, Hughes J W, Osborne T H, Beurskens M, Leonard A W, Wilson H R, Xu X Q 2011 Nucl. Fusion 51 103016Google Scholar
[18] Groebner R J, Chang C S, Hughes J W, et al. 2013 Nucl. Fusion 53 093024Google Scholar
[19] 李凯 2020 博士学位论文 (合肥: 中国科学技术大学)
Li K 2020 Ph. D. Dissertation (Hefei: University of Science and Technology of China) (in Chinese)
[20] Xu X Q, Dudson B, Snyder P B, Umansky M V, Wilson H 2010 Phys. Rev. Lett. 105 175005Google Scholar
[21] Xia T Y, Xu X Q, Dudson B D, Li J 2012 Contrib. Plasma Phys. 52 353Google Scholar
[22] Xia T Y, Xu X Q 2013 Phys. Plasmas 20 052102Google Scholar
[23] Xia T Y, Xu X Q, Xi P W 2013 Nucl. Fusion 53 073009Google Scholar
[24] Xu X Q, Dudson B D, Snyder P B, Umansky M V, Wilson H R, Casper T 2011 Nucl. Fusion 51 103040Google Scholar
[25] Duan X R, Dong J Q, Yan L W, Ding X T, Yang Q W, Rao J, Liu D Q, Xuan W M, Chen L Y, Li X D, Lei G J, Cao J Y, Cao Z, Song X M, Huang Y, Liu Yi, Mao W C, Wang Q M, Cui Z Y, Ji X Q, Li B, Li G S, Li H J, Luo C W, Wang Y Q, Yao L H, Yao L Y, Zhang J H, Zhou J, Zhou Y, Liu Yong, HL-2A Team 2010 Nucl. Fusion 50 095011Google Scholar
[26] Duan X R, Liu Yi, Xu M, et al., HL-2 A Team. 2017 Nucl. Fusion 57 102013Google Scholar
[27] Xu M, Duan X R Liu Yi, Song X M, et al., HL2A Team. 2019 Nucl. Fusion 59 112017Google Scholar
[28] Xiao G L, Zhong W L, Zhang Y P, et al., HL-2A Team. 2020 J. Fusion Energy 39 300Google Scholar
[29] Tang T F, Shi H, Wang Z H, Zhong W L, Xia T Y, Xu X Q, Sun J Z, Wang D Z 2018 Phys. Plasmas 25 122510Google Scholar
[30] Wu N, Chen S Y, Mou M L Tang C J, Song X M, Yang Z C, Yu D L, Xu J Q, Jiang M, Ji X Q, Wang S, Li B, Liu L, HL-2 A Team 2018 Phys. Plasmas 25 102505Google Scholar
[31] Ma J F, Xu X Q, Dudson B D 2014 Nucl. Fusion 54 033011Google Scholar
[32] Xi P W, Xu X Q, Xia T Y, Nevins W M, Kim S S 2013 Nucl. Fusion 53 113020Google Scholar
[33] Lortz D 1975 Nucl. Fusion 15 49Google Scholar
[34] Huang Y Q, Xia T Y, Gui B 2018 Plasma Sci. Technol. 20 045101Google Scholar
[35] 简翔 2018 博士学位论文 (武汉: 华中科技大学)
Jian X 2018 Ph. D. Dissertation (Wuhan: Huazhong University of Science and Technology) (in Chinese)
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