Stability properties and asymptotic states of a 2D tearing-unstable plasma
The nonlinearly saturated single-helicity tearing instability of a visco-resistive current-carrying plane plasma slab is investigated numerically using a 2D spectral code. The ratio of viscosity to resistivity is fixed. The equilibrium state depends on the x-coordinate only; perturbations are supposed to be periodic in the y-direction (period L) and independent of the z-direction. The Lundquist number S is chosen as bifurcation parameter, and solutions with different fixed values of the period L are investigated by varying S. Choosing a sufficiently low value of L (L = L(o)), the first branch of the set of solutions bifurcating from the given static equilibrium is found to be numerically stable up to high values of the bifurcation parameter (S = 1.0 E6). Passing to a new value L = 2L(o), that same branch presents a symmetry breaking. For a period L = 4L(o), that branch becomes unstable but a lower branch is found to be stable. Moreover, depending on the choice of the initial conditions, the evolution code may yield spatially very complicated transient states.
Bibliographic Reference: Paper presented: 13th IMACS World Congress on Computation and Applied Mathematics, Dublin (IE), July 22-26, 1991
Availability: Available from (1) as Paper EN 36294 ORA
Record Number: 199111127 / Last updated on: 1994-12-02
Original language: en
Available languages: en