Synthesis of various forms of carbon nanotubes by AC arc discharge Original Research Article

Various forms of nanotubes were produced by the AC arc discharge method at low He pressure. Some forms of nanotubes different from those which had been reported previously were found in the soot (but not the cathode deposit). These were the carbon nanocapsule, carbon cone-shaped nanotube and the carbon toroidal nanotube, respectively. The difference between the formation mechanisms by AC arc discharge and DC arc discharge was discussed.