Axisymmetric plasma plume characterization with 2D and 3D particle codes

Abstract

The expansion of a rarefied axisymmetric plume emitted by a plasma thruster is analyzed and compared with a 3D Cartesian-type and a 2D cylindrical-type simulation code, both based on a particle-in-cell formulation for the heavy species and a simple Boltzmann-type model for the electrons. The first part of the paper discusses the 2D code numerical challenges in the moving of particles, their generation within the cells, and the weighting to the nodes, caused by the radial non-uniformity and the singular and boundary character of the symmetry axis. The second part benchmarks the 2D code against the 3D one for a high-energy, unmagnetized plume with three major species populations (injected neutrals, singly-charged and doubly-charged ions) and three minor species populations (constituted by particles coming from collisional processes, such as the charge-exchange reactions). The excellent agreement found in the results proves that both plume codes are capable of simulating, with a reasonable noise level, heavy particle populations differing by several orders of magnitude in number density. For simulations with a comparable level of accuracy, the 2D code presents a ten-fold gain in computational cost, although the symmetry axis remains its weakest point, due to particle depletion there and the related weighting noise.

Coupled plasma transport and electromagnetic wave simulation of an ECR thruster

“…The mesh is finer close to the walls to improve the characterization of gradients in the vicinity of walls. An statistical population control mechanism is implemented to each species looking for an optimal number and size of macroparticles in each cell [51]. A typical number of macroparticles per cell for this type of simulations is around 300.…”

On heavy particle-wall interaction in axisymmetric plasma discharges

“…A detailed description of the PIC model used for the heavy species can be found in Refs. [16] and [22], and it is only briefly outlined here. The PIC model advances heavy species macroparticles in time and performs operations such as injecting them from dedicated boundaries, moving them according to Newton equation and the local electric field E, computing collisions (e.g.…”

Latest progress in Hall thrusters plasma modelling

“…Therefore, understanding the plasma physics involved in this region is crucial for the improvement Reviews of Modern Plasma Physics ________________________________________________________________________________ and optimization of HT. Often, models developed to study this region are fluid or hybrid (Taccogna et al 2002, 2004band Domínguez-Vázquez et al 2018b, see previous Sect. 2) considering always the electrons as Maxwellian.…”