3700 20190114115044.0 CTALK-2019-0006 Decraemer, Bieke Three-dimensional structure of a coronal streamer observed by SOHO/LASCO and STEREO/COR2 2018 2018-10-31 Helmet streamers are a prominent manifestation of magnetic structures with current sheets in the Solar corona. These large-scale structures are regions with high plasma density, overlying coronal active regions. We investigate the 3D structure of coronal streamers, observed by white-light coronagraphs (SOHO/LASCO and STEREO/COR2). 3D reconstruction of coronal structures is often ambiguous. Inverse reconstructions are difficult, so we design a forward model based on plausible assumptions about the 3D streamer structure taken from previous physical models (a plasma sheet centered around a current sheet). The streamer stalk is approximated by a plasma sheet, with electron density that is characterized by three functions describing the radial, transverse and face-on profiles respectively. We simultaneously fit the observational data from SOHO and STEREO vantage points using a multivariate minimization algorithm. We demonstrate that our model can reasonably describe the observations. NO Zhukov, Andrei Van Doorsselaere, Tom SDO2018, Ghent, Belgium bieke.decraemer@observatoire.be Contributed CTALKCONT