High harmonic fields in a rotamak plasma

Abstract

High harmonic oscillations of the magnetic fields in a rotamak plasma are measured for the first time in experiments. Experimental results indicate that besides the fundamental rotating magnetic field, harmonic fields are stimulated simultaneously. The features of the harmonics in the discharges with and without toroidal field are compared. In the case without toroidal field the harmonics are dominated by odd orders, as expected by theory. The presence of toroidal field enhances the even harmonics greatly. The ratio of amplitudes of second harmonic and the fundamental one can be as high as 45% in this case. Numerical simulation confirms that the Hall term J×B is the cause of the harmonic generation.