Linear theory of magnetic helical instabilities of plasma discharge columns

A new linear analysis for magnetic helical instabilities of are discharges in a cylindrical plasma is developed based on a set of electrostatic magnet ohydrodynamic equations. The resistive-viscous m = 1 "slow" modes with an e xternal axial magnetic field are studied in the correct electrostatic order ing for the perturbed energy equation. All quantities and the growth rates of helical instabilities are obtained analytically. In addition, the effect s of the external axial magnetic field, the are currents and the rates betw een are column radius and tube radius, on the are helical instabilities are discussed.