Self‐consistent formation of electron κ distribution: 2. Further numerical investigation

Abstract

In the preceding article (Yoon et al., 2006) the basic physics behind the generation of suprathermal electrons (the κ distribution) by means of self‐consistent processes is elucidated. In this followup paper, further numerical investigation of the electron κ formation is carried out. In particular, the underlying input physical parameters which include the plasma parameter g = 1/λD3, the electron beam‐to‐background density ratio, b/, the electron‐to‐ion temperature ratio, Te/Ti, and the ratio of average beam speed to electron thermal speed, V0/vTe, are systematically varied. It is shown that the electron suprathermal tail formation takes place over a wide range of physical parameters. It is also found that the formation of suprathermal tail appears to exhibit critical behavior in that there is a threshold beam energy below which no suprathermal population is formed, but when the energy threshold is crossed, the tail generation is greatly facilitated.