Longitudinal and transverse coupling in accelerator beam plasmas

Based on a "warm beam" model, a full 3-D electrostatic linearized stability analysis is carried out within the context of Vlasov-Maxwell equations. The coupling of longitudinal and transverse motions is included as well as arbitrary wall impedance. Numerical results show that the warm beam is rather stable for zero wall impedance. A known artifact of the model introduces the only non-resistive instability due to two rotating streams. This type of instability stabilizes when rotation frequency vanishes. For general wall impedance, Landau damping quenches instabilities provided there is sufficient longitudinal energy spread.