Ideal and resistive impurity parallel-velocity-gradient instability
Year: 2025
Type: article
Abstract: The presence of impurity ions in magnetically confined plasmas can significantly influence micro-instabilities, impacting cross-field transport and ultimately affecting fusion performance. In particular, Parallel Velocity Gradient (PVG) instability, commonly observed at the edge of fusion devices and in linear devices, can be strongly influenced by impurities. Inspired by the drift-wave models of Hasegawa-Mima and Hasegawa-Watakani, this article develops and examines two distinct fluid models: the ideal impurity-PVG model and the resistive impurity-PVG model. These models aim to investigate the impact of impurities on key properties of the PVG instability, both in the linear and nonlinear regimes. Our findings show that non-negligible impurity concentrations change the growth rates, wave-number ranges, and nonlinear saturations of these instabilities. Notably, the degree of ionization and the relative impurity flow shear can either amplify or mitigate PVG-related turbulence, depending on the impurity and overall plasma conditions. The results underscore the need for a more comprehensive treatment of multi-ion-species plasmas, particularly when impurity fractions cannot be treated as traces.
Authors: G Cuerva-Lazaro, M Lesur, O D Gürcan, J Bourgeois, C Maestracci, E Gravier, Y Kosuga
Institutions: Centre National de la Recherche Scientifique, Institut Jean Lamour, Universidad Carlos III de Madrid, Université de Lorraine, Institut Universitaire de France, École Polytechnique, Université Paris-Saclay, Observatoire de Paris, Sorbonne Université, Laboratoire de Physique des Plasmas, Institut Polytechnique de Paris, École Polytechnique Fédérale de Lausanne, Kyushu University
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4411334656