Webcam based in-vacuum tomography of plasma thruster jets

Abstract Diagnostics of plasma plumes are indispensable for both characterizing thruster performance and investigating the underlying physics of new thruster technologies. Most existing diagnostics either provide local or line-ofsight information and often require the assumption of axi-symmetry. Tomography does not have these limitations. By combining images taken at different viewing angles the 3D distribution of light intensity can be reconstructed. By the judicious use of spectral filters and a collisionalradiative model the light intensity can be related to electron temperature and plasma density. In this preliminary work we present a low-cost tomography experimental setup based on commercially available webcams which are shown to operate inside the vacuum environment. Some preliminary results are analyzed to showcase the potential of this diagnostic method.