Two-fluid magnetic island dynamics in slab geometry: Determination of the island phase velocity
نویسندگان
چکیده
The physics which determines the phase-velocity of a comparatively wide, isolated, magnetic island, formed as a result of a nonlinear tearing instability in a magnetic confinement device relying on the existence of nested magnetic flux surfaces, is investigated using a two-fluid model in slab geometry. It is found that the phase velocity is fixed by momentum transport across the magnetic flux surfaces in the region immediately surrounding the magnetic separatrix. Analytic predictions for the phase velocity are obtained, and are successfully benchmarked against the results of two-dimensional, drift-magnetohydrodynamical simulations. © 2005 American Institute of Physics. DOI: 10.1063/1.2001644
منابع مشابه
Two-fluid magnetic island dynamics in slab geometry: III - Influence of drift-wave resonances on island propagation
Previous research which analyses the dynamics of a “subsonic”, constantψ, magnetic island propagating through a two-fluid, drift-MHD (magnetohydrodynanical) plasma in slab geometry is extended to cover “supersonic” islands. In the subsonic limit, the phase-velocity of an isolated island is simply the (perpendicular) viscosity weighted mean of the unperturbed ion and electron fluid velocities. H...
متن کاملTwo-fluid magnetic island dynamics in slab geometry: I - Isolated islands
A set of reduced, 2-D, two-fluid, drift-MHD (magnetohydrodynamical) equations is derived. Using these equations, a complete and fully selfconsistent solution is obtained for an isolated magnetic island propagating through a slab plasma with uniform but different ion and electron fluid velocities. The ion and electron fluid flow profiles around the island are uniquely determined, and are everywh...
متن کاملTwo-fluid magnetic island dynamics in slab geometry. II. Islands interacting with resistive walls or resonant magnetic perturbations
The dynamics of a propagating magnetic island interacting with a resistive wall or an externally generated, resonant magnetic perturbation is investigated using two-fluid, drift-smagnetohydrodynamicald sMHDd theory in slab geometry. In both cases, the island equation of motion is found to take exactly the same form as that predicted by single-fluid MHD theory. Three ion polarization terms are f...
متن کاملHypersonic drift-tearing magnetic islands in tokamak plasmas
A two-fluid theory of long wavelength, hypersonic, drift-tearing magnetic islands in low-collisionality, lowplasmas possessing relatively weak magnetic shear is developed. The model assumes both slab geometry and cold ions, and neglects electron temperature and equilibrium current gradient effects. The problem is solved in three asymptotically matched regions. The “inner region” contains the is...
متن کاملEffect of drift-acoustic waves on magnetic island stability in slab geometry
A mathematical formalism is developed for calculating the ion polarization term in the Rutherford island width evolution equation in the presence of drift-acoustic waves. The calculation is fully nonlinear, includes both ion and electron diamagnetic effects, as well as ion compressibility, but is performed in slab geometry. Magnetic islands propagating in a certain range of phase velocities are...
متن کامل