Violating Suydam criterion produces feeble instabilities

Sangeeta Gupta, J. D. Callen, C. C. Hegna
2002 Physics of Plasmas  
Eigenmode analysis of a magnetic shear localized ideal interchange mode indicates a marginal stability condition consistent with the Suydam ͑and Mercier͒ criterion. However, the linear eigenmode analysis shows that it is not a very restrictive condition because the mode growth rate is exponentially small just above the marginal stability condition and the modes are easily stabilized by finite ion Larmor radius ͑FLR͒ effects. This suggests that for practical applications to toroidal confinement
more » ... roidal confinement experiments, the Suydam-Mercier criterion does not introduce a restrictive condition for operational limits. The criterion for robust growth appears to be almost a factor of two greater than the Suydam criterion. It is also shown that even the presence of usual nonideal effects ͑FLR, electron diamagnetic flow and resistivity͒ does not alter this higher criterion for robust growth.
doi:10.1063/1.1487865 fatcat:uhwzmo5ac5eo3a74gwrxoyysji