Criteria for second stability for ballooning modes in stellarators
نویسندگان
چکیده
منابع مشابه
Nonlinear saturation of ballooning modes in tokamaks and stellarators.
The spectral code BETAS computes plasma equilibrium in a toroidal magnetic field B = [unk]s x [unk]Psi with remarkable accuracy because the finite difference scheme employed in the radial direction allows for discontinuities of the flux function Psi across the nested surfaces s = const. Instability of higher modes in stellarators like the Heliotron E can be detected in roughly an hour on the be...
متن کاملAnderson localization of ballooning modes, quantum chaos and the stability of compact quasiaxially symmetric stellarators
The radially local magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), is examined just above the ballooning beta limit with a method that can lead to estimates of global stability. Here MHD stability is analysed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in the 3-space (s, α, θ k); s is the edge norma...
متن کاملNonlinear Stability and Saturation of Ballooning Modes in Tokamaks.
The theory of tokamak stability to nonlinear "ballooning" displacements of elliptical magnetic flux tubes is presented. Above a critical pressure profile the energy stored in the plasma may be lowered by finite (but not infinitesimal) displacements of such tubes (metastability). Above a higher pressure profile, the linear stability boundary, such tubes are linearly and nonlinearly unstable. The...
متن کاملStellarator stability with respect to global kinetic ballooning modes
Ballooning modes are usually the most dangerous ideal MHD instabilities in stellarators, but the unstable ballooning modes often have such short perpendicular wavelengths that finite Larmor radius effects are sufficient to stabilize the plasma. We use semiclassical techniques to analyse this effect. In tokamaks the ignorable toroidal coordinate leads to a simple quantization of the ballooning m...
متن کاملSub-GAM Modes in Stellarators and Tokamaks
Equations describing eigenmodes with the frequencies of the order of the geodesic acoustic frequency and the electron/ion diamagnetic frequency in toroidal plasmas are derived and analyzed, a code BOAS solving them is developed. It is shown that there exist drift-sound eigenmodes and new drift-Alfvén eigenmodes. This is done by means of an analytical consideration and numerical modelling of par...
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ژورنال
عنوان ژورنال: Physics of Plasmas
سال: 2004
ISSN: 1070-664X,1089-7674
DOI: 10.1063/1.1779227