Effects of gravity and magnetic field in production of C-60 by a DC arc discharge

We have examined the dependence of the production of C-60 on the direction of the are current with respect to the direction of gravity in a DC are dis charge in a helium gas atmosphere. The production rate decreases when the d irection of the current is opposite to that of heat convection of the heliu m gas. When a DC magnetic field is applied, the hot gas plasma in the are r egion is jetted out by the J x B force. The production rates of carbon soot and C-60 increase and depend little on the direction of gravity.