NE Seminar: “Understanding the 3D Plasma Dynamics in Open Stochastic Magnetic Fields in a Tokamak”

Date(s) - 03/02/2023
1:55 pm - 2:55 pm

Rhines 125


Min-Gu Yoo, Ph.D.

Staff Scientist
General Atomics

Dr. Min-Gu Yoo is a Staff Scientist in the Theory and Computational Science group at General Atomics. He received a Ph.D. in Nuclear Engineering from Seoul National University in 2017, and has worked at Princeton Plasma Physics Laboratory as a postdoctoral researcher from 2018‐2022.

His research interests include transport mechanisms of magnetic fusion plasmas, such as plasma start‐up and disruption, and the development of computational codes based on the first‐ principles modeling, such as the gyrokinetic particle simulations.

He has publications on plasma start‐up (Nat. Commun. 93523 (2018)) and thermal quench physics (Nucl. Fusion 61 126036 (2021)). He has received the awards of “Young Scientist in Plasma Physics” by the Korean Physical Society (2019) and the “Young Researcher Award (U40)” by the Association of Asia‐Pacific Physical Societies (2021).


In tokamaks, strong plasma instabilities like locked modes can destroy good closed magnetic surfaces and create open stochastic magnetic fields, leading to a rapid loss of plasma thermal energy, known as thermal quench. The mechanism of thermal quench has not been clearly elucidated yet due to the complex 3D topology of the stochastic magnetic field, which conventional 0D or 1D models cannot address properly.

To gain a clearer understanding, we have directly investigated the 3D plasma dynamics associated with the stochastic field by performing global gyrokinetic simulations using the GTS code and developing a novel 3D magnetic topology analysis. Our findings uncovered a novel plasma transport mechanism that contributes to the rapid loss of plasma thermal energy during the thermal quench, due to the interplay between the 3D stochastic magnetic field, ambipolar electric field, and kinetic electron and ion dynamics.

In this seminar, a comprehensive and step‐by‐step explanation of these relationships will be provided with intuitive visualizations.