Resistive ballooning modes in helical axis stellarators with longitudinal mass flow

• Published in: The Physics of fluids (1958) 1986-12, Vol.29 (12), p.4112-4118
• Main Authors: Cooper, W. A., Depassier, M. C.
• Format: Article
• Language: English
• Subjects: Exact sciences and technology; Magnetic confinement and equilibrium; Physics; Physics of gases, plasmas and electric discharges; Physics of plasmas and electric discharges
• ISSN: 0031-9171; 2163-4998
• DOI: 10.1063/1.865754

The magnetohydrodynamic equilibrium equation for magnetic confinement systems with helical symmetry and longitudinal plasma flow is derived. The incompressible resistive ballooning mode equation for systems with a coordinate of symmetry and rigid longitudinal flow is also derived. A reduced equation is then obtained by expanding the ballooning mode equation for a system with a large field period length compared with the plasma cross section. An analytic solution is obtained for a model equilibrium with circular flux surfaces. In the limit of small longitudinal velocity, the static mode width and growth rate scaling as the resistivity to the one‐third power are recovered. For small growth rates and large longitudinal velocity, these growth rates are driven by the interaction of the magnetic curvature and the centrifugal force with the radial pressure and mass density gradient, respectively, and scale linearly with the resistivity at a reduced level.