Simulations of Axisymmetric Erosion in IFR-Transported Beams

摘要

Erosion rates for relativistic electron beam propagating through low density plasma channel in the ion-focused regime are computed via axisymmetric particle simulation. We find steady-state inductive (ohmic) erosion rates that are in quantitative agreement with new theoretical results which correctly account for the relativistic dynamics of electrons at the beam head. In cases where the finite emittance of the beam is expected to be the dominant loss mechanism, the beam does not develop steady-state erosion, as suggested by previous analyses. Asymptotically, such a beam is characterized by a low emittance propulation at the beam head, a long rise length, and an erosion rate that tends toward zero. Keywords: Relativistic electron beam; Hose instability; IFR transport; Particle simulation code; Beam propagation code. (jhd)