HL-2M装置内部输运垒湍流输运的GTC模拟研究  

GTC simulation of turbulence transport at internal transport barrier of HL-2M tokamak

作　　者：肖政耀 李新霞[1,2] 王森 XIAO Zhengyao;LI Xinxia;WANG Sen(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Institute of Nuclear Physics,University of South China,Hengyang 421001,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]南华大学核物理研究所,衡阳421001

出　　处：《核技术》2024年第5期14-20,共7页Nuclear Techniques

基　　金：国家自然科学基金(No.11775108);国家重点研发计划(No.2017YFE0300406)资助。

摘　　要：HL-2M托卡马克是我国新一代磁约束聚变等离子体装置,目前已经实现了等离子体电流1 MA的高参数运行模式。本文采用回旋动理学GTC(Gyrokinetic Toroidal Code)程序,研究了具有双输运垒结构的先进运行模式下该装置内部输运垒(Internal Transport Barrier,ITB)的湍流输运。研究结果表明:ITB湍流输运呈现两次连续饱和过程,计算获得的平均离子热扩散系数约为首次饱和水平的两倍。对湍流发展的极向谱和线性色散关系的研究表明,第一次饱和湍流输运由波长kθρi~2.15的短波模式主导,而第二次饱和以kθρi~0.49的长波模式主导;同时,体系湍流的能量由短波模式反向级联到长波模式,湍流饱和阶段径向热扩散系数在输运垒位置处呈现“M”形分布。考虑等离子体带状流结构,数值模拟结果表明:该运行模式下带状流对湍流输运饱和水平没有明显的影响。此外,输运垒等离子体温度和密度梯度最大处对应的湍流饱和期的径向离子热扩散系数最低,极大地增强了对等离子体的约束。[Background]HL-2M tokamak is a new-generation magnetic confinement fusion plasma device in China,which has realized the high parameter operation mode with 1 MA plasma current.[Purpose]This study aims to investigate the turbulent transport associated with the internal transport barrier(ITB)using gyrokinetic calculations.[Methods]Numerical simulation was performed based on the gyrokinetic theory.The turbulent transport relevant to ITB was studied using the gyrokinetic toroidal code(GTC)combined with the equilibrium of HL-2M tokamak.A filtering zonal flow was considered in analyzing the influence of zonal flow on turbulent saturation level.A time evolution analysis of turbulent poloidal spectrum was conducted to investigate the effect of different wavelength modes on turbulent transport.[Results]The results show that the turbulent transport at ITB saturates twice in succession,and the calculated average ion heat transport diffusivity is approximately twice that of the first saturation level.Moreover,the short-wave mode kθρi~2.15 dominates the first turbulent transport saturation,whereas the long-wave mode kθρi~0.49 dominates the second turbulent transport saturation.Specifically,an"M"shape distribution of the radial heat transport diffusivities is obtained at the transport barrier position during the turbulent saturation period.Finally,the minimum radial heat transport diffusivity during the turbulent saturation period occurs near the ITB where a maximum plasma temperature and density gradient occurs.[Conclusions]The turbulent transport at ITB may be dominated by two types of microinstabilities at different stages of turbulence development.Turbulent energy of the system is inversely cascaded from the modes with short wavelengths to those with long-wavelengths.The results are in good agreement with the theoretical prediction of the ITB.

关 键 词：托卡马克 HL-2M装置 GTC湍流模拟 微观不稳定性 

分 类 号：TL612.1[核科学技术—核技术及应用] O532.11[理学—等离子体物理]