The helical (stability of the plasma column in a longitudinal magnetic field is investigated using the macroscopic equations of motion and continuity for ions and electrons. A finite amplitude helix is postulated to be present in the plamsa coluan and the conditions for its stability are determined. The functional form of the quasi-steady state plasma density and potential is calculated for each value of the helical amplitude Φ. For each value of φ and the applied magnetic field, the wavelength of the helix is allowed to vary in order to cal¬culate the most unstable wavelength. It is then possible to determine the stability criterion for each value of φ. These results are com¬bined with the energy balance equations for the positive column in order to determine the longitudinal electric field as a function of the applied magnetic field.
展开▼
