Numerical simulations of the wavefront distortion of inter-spacecraft laser beams caused by solar wind and magnetospheric plasmas

Plasma turbulence may lead to additional wavefront distortion of inter-spacecraft laser beams during the operation of spaceborne gravitational wave (GW) observatories, e.g. TianQin. By making use of the Space Weather Modelling Framework (SWMF) model and realistic orbit data for the TianQin constellation, the characteristic parameters of the plasma turbulence present at the TianQin orbit are obtained. As a first step, this work is based on the assumptions that the cold plasma approximation is valid and that the effects of the electromagnetic field induced by charge separation within the Debye length on the laser’s wavefront can be ignored. An atmospheric turbulence–laser interaction model is then applied to analyze the effects of the plasma turbulence on the inter-spacecraft laser’s wavefront. The preliminary results show that the wavefront distortion caused by the plasma turbulence is 10^–9 rad, which is significantly less than the designated error budget, i.e. 10^–6 rad, and thus will not affect the laser interferometry.