Symmetry breaking bifurcations of a current sheet
Abstract
Using a time evolution code with periodic boundary conditions, the viscoresistive hydromagnetic equations describing an initially static, planar current sheet with large Lundquist number have been evolved for times long enough to reach a steady state. A cosh2 x resistivity model was used. For long periodicity lengths Lp, the resistivity gradient drives flows that cause forced reconnection at X point current sheets. Using Lp as a bifurcation parameter, two new symmetry breaking bifurcations were found: a transition to an asymmetric island chain with nonzero, positive, or negative phase velocity, and a transition to a static state with alternating large and small islands. These states are reached after a complex transient behavior, which involves a competition between secondary current sheet instability and coalescence.
- Publication:
-
Physics of Fluids B
- Pub Date:
- March 1990
- DOI:
- Bibcode:
- 1990PhFlB...2..508P
- Keywords:
-
- Asymptotic Methods;
- Branching (Mathematics);
- Current Sheets;
- Magnetohydrodynamic Stability;
- Plasma Currents;
- Tearing Modes (Plasmas);
- Fourier Transformation;
- Incompressible Fluids;
- Rayleigh-Benard Convection;
- Stream Functions (Fluids);
- Vorticity;
- Plasma Physics