The discovery of carbon nanotubes has motivated great interests about their atomic and electronic structures and possibilities for technological applications. The electric arc method is now widely used to prepare carbon nanotubes. We actually characterise the arc plasma by changing some parameters as pressure, type of catalysts and anode's structure in order to relate the influence of plasma to the structural characteristics of the various carbon nanostructures obtained and analysed by high resolution transmission electron microscopy. Radial temperature was deduced from Boltzmann plots using a group of well resolved components of the P(0,0) branch.
By changing some parameters we obtained high proportion of SWNT and DWNT isolated or ropes.