MAGNETOHYDRODYNAMIC INSTABILITY OF AN ANNULAR GAS JET OF DOUBLE PERTURBED INTERFACES

摘要

The magnetohydrodynamic (MHD) instability of an annular gas jet of double perturbed interfaces is analyzed. The MHD basic equations are linearized and solved. A general stability criterion is derived and discussed analytically and the results are confirmed numerically. Several stability criteria are recovered from the present relation. The capillary force is, acting along the gas-liquid interface, destabilizing only for small axisymmetric wavelengths and stable for all the rest. The electromagnetic forces in the gas and liquid regions are strongly stabilizing for all wavelengths in all modes of disturbance, and this is interpreted physically. Above a certain value of the applicable magnetic field, the electromagnetic force influences suppress the capillary instability and stability sets in. The thicker the radius of the liquid cylinder relative to that of the gas cylinder, the greater the destabilizing influence and the larger the MHD unstable domains for the same value of the fundamental basic magnetic field. Physically, the suppression of the capillary instability is due to the fact that the Lorentz force leads to twisting and bending of the lines of force and, moreover, it gives a measure of rigidity to the conducting fluid.