Wave propagation and absorption in a helicon plasma thruster and its plume

Abstract

Abstract A two-dimensional, full-wave, frequency domain, cold plasma model is used to study electromagnetic power propagation and absorption in a helicon plasma thruster, including its far plume region and surrounding space. Results show that a fraction of power is absorbed in the plume region, and that the power deposition in the source is essentially unperturbed by the simulation domain size, the presence of metallic obstacles, or the plasma density in the environment. An electron–cyclotron resonance (ECR) surface always exists downstream that effectively prevents radiation to the space beyond along the plume. In the presence of an overdense environmental plasma, like the one expected in a vacuum chamber, fields are fully evanescent beyond this transition, and vacuum chamber boundary conditions affect but little the wavefields before this surface. In the absence of an environmental plasma, a double wave regime transition exists at the interface between the plasma and vacuum that hinders accurate numerical simulation in the plume region.