Resistivity profile and instability of the plane sheet pinch

• Main Authors: Seehafer, Norbert, Schumacher, Jörg
• Format: Others
• Language: English
• Published: Universität Potsdam 1998
• Subjects: Physics
• Online Access: http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-14686; http://opus.kobv.de/ubp/volltexte/2007/1468/

The stability of the quiescent ground state of an incompressible, viscous and electrically conducting fluid sheet, bounded by stress-free parallel planes and driven by an external electric field tangential to the boundaries, is studied numerically. The electrical conductivity varies as cosh–2(x1/a), where x1 is the cross-sheet coordinate and a is the half width of a current layer centered about the midplane of the sheet. For a <~ 0.4L, where L is the distance between the boundary planes, the ground state is unstable to disturbances whose wavelengths parallel to the sheet lie between lower and upper bounds depending on the value of a and on the Hartmann number. Asymmetry of the configuration with respect to the midplane of the sheet, modelled by the addition of an externally imposed constant magnetic field to a symmetric equilibrium field, acts as a stabilizing factor.