Toroidal magnetodynamic stability of cylindrical fluid jet

The hydromagnetic stability of a fluid jet under the combined influence of the electromagnetic (with toroidal varying field) and capillary forces has been developed. A general dispersion relation valid for all modes of perturbation is derived. The magnetic fields interior and exterior the fluid jet are stabilizing. The capillary force is destabilizing for small domain in the axisymmetric mode while it is stabilizing for all the rest. The magnetic fields increase the capillary stable domains and at the same time cause the shrinking those of instability. Above a certain value of the relative magnetic field strength, the capillary instability is depressed and then stability sets in. In spite of the field interior the fluid is non-uniform, however, we found that it has a strong stabilizing influence.