Regenerative Soot: A cusp field, graphite hollow cathode, carbon cluster   ion source
  An all carbon hollow cathode ion source with a specially designed cusp magnetic field Bz as a function of radius and theta is described. Velocity spectra from this source has shown that carbon cluster synthesis is taking place as a function of the source design, discharge parameters and the state of sooting. The cusp magnetic field seems to establish two distinct discharge regions within the source. The first is a narrow annular ring that is 2 mm thick and 15-20 mm long with restricted axial and radial extent of the cusp field. Here the source gas ionizes. The carbon atoms sputter of the cathode walls and subsequently get ionized. The other one is a cylindrical plasma region with the entire axial range of Bz. In this region the dynamics of the soot formation from the plasma constituent on the cathode walls seems to be related to the carbon clustering processes 
Shoaib Ahmad and Tasneem Riffat
cond-mat.mes-hall