Kinetic Alfvén waves in a deuterium-tritium fusion plasma with slowing-down distributed α-particles

Abstract

The dispersion relation and damping rate of kinetic Alfvén waves (KAWs) in a deuterium-tritium fusion plasma with slowing-down distributed α-particles are investigated using the kinetic theory. The variations of wave frequency and damping rate with respect to the α concentration (nα /n e) and perpendicular wave number (k ⊥) are studied from a numerical way. The results show that the fluctuation of α concentration slightly affects the frequency and damping rate of KAWs at low nα /n e. In addition, the frequency and the damping rate increase as the k ⊥ and the background temperature T e increase. For comparison, the calculations are performed also in the case of α-particles following an equivalent Maxwellian distribution. For a given k ⊥, the value of the frequency obtained in the slowing-down distribution case is smaller than that obtained in the Maxwellian distribution case. Conversely, the value of the damping rate obtained in the slowing-down distribution case is slightly larger than that obtained in the Maxwellian distribution case.