报告题目：Effect of Toroidal Alfven Eigenmode Nonlinearity on Edge Localized Mode in HL-2A NBI Heated H-mode Plasmas
报告人：陈伟研究员
报告时间：2024年11月6日上午8:00
报告地点：物理科技楼409
报告摘要：Prior to ELM crash, shear Alfvenic wave fluctuations are observed in HL-2A NBI H-mode Plasmas. These Alfvenic fluctuations principally come from the contributions of unstable toroidal Alfven eigenmodes (TAEs). There are strong nonlinear mode couplings between dominant TAEs with n=3-4 and low frequency MHD mode (kink or fishbone) with n=1 before the ELM crash. The pitch-fork phenomena of TAEs grow explosively and become an explosive instability. The explosive events have two kind fine structures, i.e., multi-modes and pitch-fork. The two kind structures can coexist, but the strong nonlinear mode coupling induces that the pitch-fork weakens or vanishes and the modes blow-up in finite-time, and this indicates that the nonlinear mode coupling may redistribute energetic-ions, destroy hole-clump pairs in the phase-space, and maybe induce three-wave mixing nonlinearly. As a consequence, we find and identify firstly that the TAE nonlinear dynamics triggers the onset of ELMs and pedestal collapse within several hundred Alfven times, and they are correlated to the irregular shape ELM features. The experimental result manifests that the nonlinear dynamics of Alfven fluctuations may furnish an additional perturbation of the energetic-particle pressure in the pedestal, and this pressure perturbation can move closer to MHD limit, so that the ELM trigger is determined by the nonlinear mode coupling and edge stability. These findings can help to understand the triggering mechanism of an ELM event.
报告人简介：陈伟，研究员、博导、国家自然科学基金杰出青年项目获得者、国务院政府特殊津贴专家、国家重点研究计划项目首席科学家、国际原子能机构高能量粒子技术会议咨询委员会成员。大连理工大学兼职教授、清华大学卓越工程师计划企业导师、科技部、国家基金委、中国科协和四川省科技厅等项目会议评审专家。主持国家重点研发计划项目一项和国家自然科学基金四项。在美国物理评论快报和核聚变等杂志上发表SCI论文百余篇，其中第一和通讯作者论文四十余篇，获授权专利多项，在国际聚变能大会等国内外学术会议上做邀请和口头报告二十余次。先后获蔡诗东等离子体物理学奖、胡济民教育科学奖、全国等离子体优秀青年创新奖和亚太等离子体杰出青年研究奖, 英国皇家物理学会杰出审稿人奖等。
