Particle-in-cell (PIC) tools for simulation of electrodynamic bare tether plasma interactions

Summary form only given. Electrodynamic tethers (EDTs) can be used for near Earth space missions to produce thrust to raise and lower a satellite orbit or change its inclination, and, in drag inducing (de-orbit) mode, EDTs can provide electrical power to the satellite. Recently there has been renewed interest in bare wire EDTs that operate at larger current and voltage levels, and hence it is becoming important to understand current collection along the positively biased regions of the tether and the plasma interactions these high current EDTs will induce. In this work, we describe numerical and experimental studies of EDTs with the goal to develop and validate computational tools for researchers who are designing tethers for future missions. In our numerical studies we will utilize two particle-in-cell codes VORPAL and OOPIC Pro. VORPAL is a 1-D, 2-D and 3-D massively parallel electromagnetic simulation code and OOPIC Pro is a 2-D parallel electromagnetic simulation code with user-friendly GUI interfaces. We will develop suitable boundary conditions such as quasi-neutrality and open boundaries to simulate accurately the tethers operation in space. We will benchmark our 2-D electrostatic numerical simulations against other published analytical and numerical results. In addition, we will conduct full electromagnetic simulations to consider self-induced magnetic field effects. On the experimental side, tests on thin tether tapes will be conducted in a vacuum facility equipped with a plasma source developed by Rubin et al. that replicates the streaming plasma encountered by satellites in low Earth orbit. These experiments will characterize electron collection to the tape tethers under varying electrical bias and angle of attack.