The Structure of Carbon Arc at Fullerene Synthesis

In this paper, the arc between graphite electrodes under conditions favorable for fullerene synthesis (I = 60-120 A, U = 20-40 V, L = 1-6 mm, p = 1-200 torr) is considered. The time-spatial structure of the arc is studied by means of high-speed imaging. For the first time, it was found out that the arc in question exists in two modes. In the nonstationary mode, the arc looks like two contracted spiral channels coming from an anode spot and revolving on lateral surface of cylindrical electrodes with a frequency of 10-20 kHz. The observed unsteadiness arises from the development of overheating instability of heterogeneous plasma.