“高端外国专家引进计划”系列报告——Taik Soo Hahm

==== Academic Seminars No.127 ====

时间：2022年9月23日  周五  09:00

方式：Zoom会议 335 925 3293（密码：123456）

链接：https://us06web.zoom.us/j/3359253293?pwd=ZGo1dkR3dTV2aytYVHllOUYvZjZ5QT09

邀请人：王璐 教授

报告人：Taik Soo Hahm (Seoul National University)

题目：Vortex flow dynamics in magnetic island

摘要：

Role  of ExB shear flow associated with a vortex inside a large static  magnetic island on micro-turbulence has been investigated. In the  derivation, quasi-helical symmetry of a magnetic island (MI) has been  utilized. Due to the elongation of the MI and incompressibility of the  ExB flow, the shearing rate near X-points is much lower than that near  the mid-plane of the MI on the same flux surface. This calculation of  ExB shearing profile and, in particular, minimal ExB shear near the  X-points [1] is consistent with the recent experimental finding that  turbulence tends to spread into an MI through regions around the  X-points [2]. In addition, the vortex tends to be well-sustained in a  large MI in the absence of collisions, but develops into more  complicated structure in a long term as the toroidal precession drift of  trapped particles break the quasi-helical symmetry [3]. Similarities  with the previous corresponding works in axisymmetric tokamak geometry  [4,5] will be discussed.

References:

[1] T.S. Hahm et al, Phys. Plasmas 28, 022302 (2021)

[2] K. Ida et al., Phys. Rev. Lett. 120, 245001 (2018)

[3] G.J. Choi and T.S. Hahm, Phys. Rev. Lett. 128, 225001 (2022)

[4] T.S. Hahm and K.H. Burrell, Phys. Plasmas 2, 1648 (1995)

[5] M.N. Rosenbluth and F.L. Hinton, Phys. Rev. Lett. 80, 724 (1998)

报告人简介：

Taik Soo Hahm，美国物理学会会士，韩国首尔国立大学核聚变工程系教授，曾任普林斯顿大学首席研究物理学家、杰出实验研究员，韩国国家聚变研究所先进技术研究中心主任。先后获得亚太物理学会Chandrasekhar 奖、等离子体物理和技术开发考尔卓越奖、首尔国立大学自然科学学院最优毕业生、国会主席奖等荣誉。