Steady-state plasma production and fluid flow in ion beams with step-function density profiles

Abstract

The steady-state fluid equations for plasma production and transverse flow in an ion beam with a step-function density profile are solved exactly in both slab and cylindrical geometries. The beam edge is treated as both a neutral and a non-neutral sheath. In the former, the beam density falls from its value inside the beam to zero in a distance much greater than a Debye length, while in the latter the Debye length is much greater than the beam falloff distance. Physical solutions with plasma density profiles which decrease monotonically from the beam center are shown not to exist for negative ion beams with a non-neutral sheath.