Stability of a cylindrical plasma in the presence of a monotonic field—II

The stability of an incompressible inviscid, perfectly conducting cylindrical plasma against azimuthal disturbances in the presence of a monotonic decreasing magnetic field having a constant pitch is discussed by using energy principle. The results obtained by this principle are compared form = 1 mode (which is a dangerous mode in which there is a lateral shift of the entire column) with that obtained by normal mode analysis. It is found thatm = 1 mode is always unstable. Further, an axial line current, external axial field and the surface tension tend to stabilisem ≠ modes.