Electrothermal waves and instabilities in partially and fully ionized plasmas

The linear and fully developed electrothermal instability in partially ionised gases is shown. For K parallel to B there is good experimental evidence that an electrothermal instability occurs in the early stages of a gas discharge. The filamentary structure persists throughout the time history. Preliminary results on radial thermal instabilities indicate that a filamentary structure of the order of an ion Larmor radius in width can occur. Also the boundary conditions at the wall indicate that there might be a problem in obtaining a low pressure in this region. (Auth.)