Coaxial Microwave Plasmas in Argon: Radial Contraction,   Self-Organization and more Exotic Phenomena
  A coaxial microwave plasma setup was designed for investigation by optical and laser diagnostics. The plasma is sustained by two microwave power sources located at both ends of a coaxial line. This allows generating an axially homogeneous glow discharge at low pressure. For increasing pressures, this glow-like mode is found to be unstable and various self-organized patterns are observed including finger-like structures which can be sustained after the visible end of the plasma column. 
E.A.D. Carbone, S. H\"ubner, E. M. van Veldhuizen, A. Schrader, S.   Nijdam, G.M.W. Kroesen
physics.plasm-ph