Kinetic instability observations in the Gas Dynamic Trap

The spatial structure of electromagnetic plasma-induced waves has been defined in the high-energy content regime of the Gas Dynamic Trap operation. The waves with the smallest non-axisymmetric azimuthal mode m = 1 propagating in the direction of ion-diamagnetic drift current have been observed. Polarization of the excited waves changes their direction from that of ion gyration to that of electron gyration as the distance from the symmetry axis is increased. These data confirm the assumption that the instability observed is the Alfven ion-cyclotron one. The longitudinal velocity range of particles responsible for the instability excitation has been obtained from the experiment. This range is consistent with the theory.