The electromagnetic ion beam instability and energy loss of fast alpha particles

A high-speed ion beam directed along a uniform magnetic field can excite an electromagnetic ion beam instability. The linear and second-order theory of this instability is considered. If the beam is sufficiently dense, and if the saturation level is sufficiently high, the anomalous energy loss distance is much shorter than the classical mean free path. A possible application to alpha-particle energy loss in a linear multiple mirror theta pinch is discussed.