Local stability of fluid plasmas in the presence of flows

Abstract

The Mercier and ballooning instabilities are considered for plasmas with toroidal and poloidal flows in an axisymmetric torus. The stability criteria are derived and compared for the two instabilities. It is found that ballooning modes impose more severe requirements for plasma stability than the Mercier condition.

Non-exponential hydrodynamical growth in density-stratified thin Keplerian discs

“…Indeed, recent calculations in real thin disc geometry have demonstrated the efficiency of such processes to significantly amplify initially small perturbations, and thus to generate intensive hydrodynamical activity in the otherwise centrifugally stable Keplerian discs (Umurhan et al 2006;Rebusco et al 2009). Such non-modal growth of perturbations has also been obtained for ballooning modes in magnetized rotating plasmas in tokamaks (Chun & Hameiri 1990). The two routes described above are shown in the current work to diverge from a single unified comprehensive stability analysis in real thin disc geometry.…”

Tokamak equilibria and stability with arbitrary flows

“…Investigations on the local (Suydam) criterion in the presence of flows have been carried out by Hameiri [22], Wright et al [23] and also by Bondeson et al [20]. The generalization of the Mercier criterion to include the effect of flows has been obtained by Chun and Hameiri [24]. The effect of flow on the stability to kink modes has been studied by Bondeson and Iacono [25].…”