Simulation and modeling of PEGASES thruster operated with iodine
Résumé
The LPP has built an expertise on the physics of different types of plasma thrusters for over 12 years. An efficient plasma generation is crucial to optimize the overall efficiency of a plasma thurster. Radio-frequency (RF) inductively coupled plasma (ICP) discharges are among the most popular ways to achieve this goal for ion gridded thrusters. PEGASES and NEPTUNE thrusters are two cathode-less prototypes designed at LPP that feature an ICP discharge with gases such as argon, xenon, sulfure hexafluoride (SF6), and iodine (I2). In order to better understand the operation of these thrusters, a benchmarked 2D PIC-Monte-Carlo code initially designed for r-θ simulation of Hall thrusters was adapted to ICP simulation. The heating mechanism is assumed to occur in the direction perpendicular to the simulation plane and is localized in a skin depth near the heating antenna. The power absorbed by the plasma over one RF period is the control parameter of the simulation and the plasma potential is derived from Poisson equation. The electron density at steady state is proportional to the input power and the electron temperature decreases when the background gas pressure increases. The plasma potential is approximately five times the electron temperature given in electron-volts. The plasma potential in steady-state is lower for iodine than for argon. The results are consistent with global models of plasma discharges.