Theory of coupled resistive drift and resistive drift ballooning instabilities in fusion plasma

Umer Rehman; Ahmad Ali; Shakeel Mahmood

doi:10.1016/j.heliyon.2021.e08020

Theory of coupled resistive drift and resistive drift ballooning instabilities in fusion plasma

Heliyon. 2021 Sep 20;7(9):e08020. doi: 10.1016/j.heliyon.2021.e08020. eCollection 2021 Sep.

Authors

Umer Rehman¹, Ahmad Ali², Shakeel Mahmood¹

Affiliations

¹ Department of Physics, Air University, E-09 Complex, Islamabad, 44000, Pakistan.
² National Tokamak Fusion Program, Islamabad, 44000, Pakistan.

Abstract

Drift wave instabilities (DWI) associated with the two-fluid dynamics seems to be responsible for anomalous transport in modern day tokamaks. Ballooning instabilities tend to exchange flux tubes of different pressure, resulting in convective transport. The micro-level turbulence (drift wave) is coupled with the macro-level (ballooning mode) dynamics in fusion experiments. The co-existence of DWI and drift ballooning instabilities (DBI) is discussed in this work using a four-field plasma model. The formulation preserves both the microscopic and macroscopic dynamics of plasma. To demonstrate the coupling, a new dispersion relation is derived to analyze stability of the coupled modes in a non-uniform magnetized plasma. Linear stability of coupled drift-ballooning and drift-acoustic modes have been explored. The two-fluid effect (micro-level influence) through diamagnetic drift frequency for electrons and curvature drift frequency on unstable modes are demonstrated.

Keywords: Coupled modes; Drift wave; Fusion plasma; Plasma instability.