Linear spread mass modeling of the ion hose instability

An important instability in the propagation of an intense relativistic electron beam in a plasma channel is the ion hose, or ion resonance instability. In this instability, transverse oscillations of the beam electrons and channel ions electrostatically couple and grow. This mode has been experimentally identified as disrupting relativistic E-beam propagation in a tenous gas over short distances (≅.5m). The ion resonance instability has been investigated theoretically and numerically, using the spread mass model. In both studies the beam and channel profiles were assumed to be described by Bennett profiles of equal mean radii. The authors extended the above two studies to included values of S=(r/sub b//r/sub c/)/sup 2/ smaller than unity. Such values of s are thought to be stabilizing to this mode, since the electrostatic coupling between the beam and channel is diminished