CUMULATIVE HOSE INSTABILITIES OF A MAGNETICALLY SELF-FOCUSED SLAB ELECTRON-BEAM

Transverse instabilities are investigated for the slab analog of the B ennett equilibrium of a magnetically self-focused relativistic electro n beam propagating through a plasma. Two kinds of plasma are considere d: a channel matched to the beam and a broad uniform plasma. The high- frequency electrostatic transverse two-stream instability and the lowe r-frequency resistive-hose instability are treated analytically with a distributed tune (''mass'') model. Asymptotic growth is computed for each instability in various regimes, and analytic results are benchmar ked against numerical solutions of the linearized system and particle- in-cell simulations. It is found that in the limit of large collisionl ess skin depth the electrostatic hose is the more virulent mode of bea m breakup. Numerical examples are discussed for parameters in the rang e considered for plasma focusing of the asymmetric beams of interest i n high-energy physics.