A self-consistent model of helicon discharge

Abstract

We developed a self-consistent model of helicon discharges, motivated by a number of applications. One example is a plasma-based space propulsion system that employs a helicon discharge as its plasma source. Our study of helicon discharges involves two steps. An electro-magnetic wave solver is first developed to study wave phenomena and power deposition. In this work, we model a resonant response of the discharge observed in a recent experiment. The radially localized helicon (RLH) wave is identified as the primary mechanism of rf-power deposition into the plasma. The second step is to take into account electron heat transfer and ion transport so that a self-consistent simulation can be performed. As a case study of validating the model, we simulated one of Boswell’s early experiment in which a jump of plasma density in a scan of external magnetic field is observed. Calculation shows that a classical heat transport is unable to sustain the plasma density profile observed in the experiment. Solutions comparable to the experiment are obtained only when extra heat conductivity is used. The density profiles and excited wave-lengths are in good agreement with the experiment. Especially, the dual-stable solution of the simulation supports the observed plasma density jump.