Work

Toroidal Alfvén mode instability driven by plasma current in low-density Ohmic plasmas of the spherical tori

Year: 2024

Type: article

Abstract: Due to intrinsically low magnetic fields, at low density the drift speed of the current-carrying electrons in spherical tokamaks can exceed fraction of the Alfvén speed sufficient for the excitation of the Alfvén gap modes. A particular case of the toroidal mode, observed during minor disruptions in Ohmic shots on SUNIST [Liu et al., Phys. Plasmas 23, 120706 (2016)], is considered in the present communication. Due to the negligible effect of the electron pressure gradient, the growth rate scales linearly with the drift speed, with slope inversely proportional to electron thermal velocity. In the absence of continuum damping, the threshold value of the drift speed for TAE excitation is independent of electron temperature.

Source: Physics of Plasmas

DOI: 10.1063/5.0223920

Authors: V. S. Marchenko, S. N. Reznik

Institution: Institute for Nuclear Research

Language: English

Topic: Magnetic confinement fusion research

Subfield: Nuclear and High Energy Physics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Funder: Fusion Energy Sciences

Award: G2003352249