时间：2025年12月30日（周二）14:00

地点：紫金港校区海纳苑8幢324教室

报告题目：Study of neoclassical transport characteristics by MONTS code in the CFQS quasi-axisymmetric stellarator

报告人：杨浪

摘要： 

The construction of the CFQS-T, the world's first experimental quasi-axisymmetric stellarator (QAS) device, was completed in July 2024. Presently, commissioning activities are underway for peripheral equipment such as the power supply system for magnetic coils, as preparations are made for the initiation of the first plasma. As part of our research to explore neoclassical diffusion properties in CFQS plasmas, we have been developing the Monte Carlo Neoclassical Transport Simulation (MONTS) code, incorporating the orbit Monte Carlo method and δf Monte Carlo Method. The orbit Monte Carlo method tracks all particle positions to assess radial transport. Therefore, our study aims to comprehensively investigate the impact of finite beta (volume-averaged beta, <β>) on neoclassical transport characteristics in CFQS using the orbit Monte Carlo method. Examination of neoclassical diffusion properties in CFQS involves various scenarios, with a focus on electron and ion particle fluxes influenced by radial electric fields. Analysis of neoclassical diffusion coefficients and plasma parameters for low beta and high beta cases reveals that the electron roots of the ambipolar condition can contribute to effective confinement in CFQS across both low beta and high beta values. To enhance the assessment of neoclassical transport features in CFQS, MONTS incorporates the δf Monte Carlo Method, which evaluates the collision operator and particle weight variation in both time and space. The monoenergetic diffusion coefficients, including radial transport coefficient and bootstrap current coefficient, have been benchmarked by comparing results obtained from the orbit Monte Carlo method and the Drift Kinetic Equation Solver (DKES) code. To enhance accuracy, momentum conservation in Coulomb collisions has been considered. The investigation of local mean radial velocities (V_r) derived from radial particle fluxes, with and without momentum conservation elements, has been investigated. To further assess the magnitude of bootstrap currents, a multi-energetic particle transport model has been integrated into the MONTS code. The bootstrap current density has been preliminarily benchmarked by assuming profiles of density and temperature gradients, which suggests the potential for the MONTS code to be combined with actual experimental parameters in the future.

个人简介：

杨浪，博士。2025年获综合研究大学院大学核科学（聚变方向）理学博士学位，先后于西安石油大学获学士学位、西南交通大学获硕士学位。主要研究方向为仿星器磁位形下的粒子轨道拓扑结构分析，并在准环对称仿星器磁位形中，基于粒子轨道理论、引入碰撞项，利用蒙特卡洛方法开发MONTS代码，以探究新经典输运性质。未来拟进一步完善MONTS代码，并持续优化仿星器磁位形设计。

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