Stereoscopic measurements of coronal Doppler velocities

Context. The Solar Orbiter mission, with an orbit outside the Sun-Earth line and leaving ecliptic plane, opens up opportunities for combined analysis of measurements obtained by solar imagers spectrometers. For first time different space spectrometers will be located at wide angles to each other, allowing three-dimensional (3D) spectroscopy atmosphere. Aims. aim this work is prepare a methodology facilitate reconstruction 3D vector velocities from two stereoscopic sight (LOS) Doppler velocity using Spectral Imaging Coronal Environment (SPICE) on board near-Earth spectrometers, while widely separated in space. Methods. We developed libraries designed earlier STEREO but applied spectroscopic data Hinode mission Dynamics Observatory. used well-known methods static dynamic rotation stereoscopy extreme ultraviolet (EUV) triangulation optically thin coronal EUV plasma emissions. new algorithms analytical geometry determine loops. Results. demonstrate our approach vectors flows along ‘open’ ‘closed’ magnetic This technique actual situation spacecraft separations during nominal phase: SPICE versus Interface Region Spectrograph (IRIS) imaging spectrometer. summarise how these observations can coordinated.