2D OOPIC simulations of the Helicon Double Layer

The Australian National University and the Ecole Polytechnique in Palaiseau obtained experimental results of current free helicon double layer (DL) originating with electropositive and electronegative gases. The experimental evidence of the double layer envisages tantalizing performance of a thruster exploiting this effect. The paper is intended to present part of the results obtained by a deep numerical investigation on Double layer formation, stability and characteristic and to explore the applicability of this concept to space mission. The analysis has been conducted using XOOPIC, a 2-D numerical code of Berkeley University. We focused our study on the analysis of the following aspects: effects of the source walls characteristics and geometry, DL formation and stability, influence of magnetic field and neutral pressure, ions' beam divergence and flux detachment. We found that for higher neutral pressures the potential jump reduces whereas an electrically biased wall can increase its amplitude. The thrust and specific impulse have been evaluated for a low density discharge. The 2-D code results are here presented and compared with experimental data provided in literature.