Effects of the plasma conductivity on transverse instabilities in high-intensity ion beams

Summary form only given, as follows. Intense ion beams produced in high energy accelerators and transport systems have wide range applications, including basic scientific research, spallation neutron sources, nuclear waste transmutation, and heavy ion fusion, to mention a few examples. Ion beams propagating through preformed plasma may be subject to various instabilities that can cause deterioration of the beam quality. The most deleterious instabilities in the intense ion beams propagating through a preformed plasma channel are the electron-ion two stream and the resistive-hose instabilities, which disturb the ion beam sideway, thereby pushing it out of channel and eventually losing it. The electron-ion two stream instability occurs in collisionless plasma, developing a dipole oscillation between the beam and plasma column segments. This dipole oscillation caused by the Coulomb force overshoots and grows. On the other hand, when a current-carrying beam moves through conducting plasma, its self-magnetic field may follow the beam with a delay time called the magnetic decay time. The magnetic field lines are frozen into the plasma, pulling back the distorted beam segment if the plasma is highly conducting. This restoring mechanism, which leads to the resistive hose instability, overshoots and grows due to the motionless resistive plasma medium. Basic properties of these two instabilities will be presented. The transformation from the two-stream instability to the resistive-hose instability will be traced by properties of the preformed plasma channel.