Simplify The Analysis Of The Helical Instability Of Arc And Gas Flow Stabilizing Effect

Nowadays, with the wide application of Arc discharge plasmas, there is a badly need for the research of it. In previous works, it is very difficult to acquire the exactly results due to the complexity of the MHD equation. In this paper, we ignore some terms based on the analysis of the energy equation so we can resolve the problems easily compared to previous works. We come to these conclusion: the helical instability growth rate exacerbate while the arc current is increased; the applied positive axial magnetic field stabilize the middle and long wavelength disturbance while the applied minus axial magnetic field stabilize the short wavelength disturbance; and arc column with electrical conductivity of the parabolic distribution also stabilize the long wavelength disturbance apparently. As a result of the equation complexity, there isn any research about the effect of applied airflow on arc plasma helical instability. We give the airflow expression and come to a conclusion that the applied airflow stabilized short wavelength disturbance obviously in this paper.