The Polarimetric and Helioseismic Imager on Solar Orbiter
Creators: name: Solanki, S. K.
name: Iniesta, J. C. del Toro
name: Woch, J.
name: Gandorfer, A.
name: Hirzberger, J.
name: Alvarez-Herrero, A.
name: Appourchaux, T.
name: Pillet, V. Martínez
name: Pérez-Grande, I.
name: Kilders, E. Sanchis
name: Schmidt, W.
name: Cama, J. M. Gómez
name: Michalik, H.
name: Deutsch, W.
name: Fernandez-Rico, G.
name: Grauf, B.
name: Gizon, L.
name: Heerlein, K.
name: Kolleck, M.
name: Lagg, A.
name: Meller, R.
name: Müller, R.
name: Schühle, U.
name: Staub, J.
name: Albert, K.
name: Copano, M. Alvarez
name: Beckmann, U.
name: Bischoff, J.
name: Busse, D.
name: Enge, R.
name: Frahm, S.
name: Germerott, D.
name: Guerrero, L.
name: Löptien, B.
name: Meierdierks, T.
name: Oberdorfer, D.
name: Papagiannaki, I.
name: Ramanath, S.
name: Schou, J.
name: Werner, S.
name: Yang, D.
name: Zerr, A.
name: Bergmann, M.
name: Bochmann, J.
name: Heinrichs, J.
name: Meyer, S.
name: Monecke, M.
name: Müller, M. -F.
name: Sperling, M.
name: a, D. Álvarez Garcí
name: Aparicio, B.
name: Jiménez, M. Balaguer
name: Rubio, L. R. Bellot
name: Carracosa, J. P. Cobos
name: Girela, F.
name: Expósito, D. Hernández
name: Herranz, M.
name: Labrousse, P.
name: Jiménez, A. López
name: Suárez, D. Orozco
name: Ramos, J. L.
name: Barandiarán, J.
name: Bastide, L.
name: Campuzano, C.
name: Cebollero, M.
name: Dávila, B.
name: Fernández-Medina, A.
name: Parejo, P. García
name: Garranzo-García, D.
name: Laguna, H.
name: Martín, J. A.
name: Navarro, R.
name: Peral, A. Núñez
name: Royo, M.
name: Sánchez, A.
name: Silva-López, M.
name: Vera, I.
name: Villanueva, J.
name: Fourmond, J. -J.
name: de Galarreta, C. Ruiz
name: Bouzit, M.
name: Hervier, V.
name: Clec'h, J. C. Le
name: Szwec, N.
name: Chaigneau, M.
name: Buttice, V.
name: Dominguez-Tagle, C.
name: Philippon, A.
name: Boumier, P.
name: Cocguen, R. Le
name: Baranjuk, G.
name: Bell, A.
name: Berkefeld, Th.
name: Baumgartner, J.
name: Heidecke, F.
name: Maue, T.
name: Nakai, E.
name: Scheiffelen, T.
name: Sigwarth, M.
name: Soltau, D.
name: Volkmer, R.
name: Rodríguez, J. Blanco
name: Domingo, V.
name: Sabater, A. Ferreres
name: Blesa, J. L. Gasent
name: Martínez, P. Rodríguez
name: Caudel, D. Osorno
name: Bosch, J.
name: Casas, A.
name: Carmona, M.
name: Herms, A.
name: Roma, D.
name: Alonso, G.
name: omez-Sanjuan, A. G\'
name: Piqueras, J.
name: Torralbo, I.
name: Fiethe, B.
name: Guan, Y.
name: Lange, T.
name: Michel, H.
name: Bonet, J. A.
name: Fahmy, S.
name: Müller, D.
name: Zouganelis, I.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: This paper describes the Polarimetric and Helioseismic Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument to observe the Sun from outside the Sun-Earth line. It is the key instrument meant to address the top-level science question: How does the solar dynamo work and drive connections between the Sun and the heliosphere? SO/PHI will also play an important role in answering the other top-level science questions of Solar Orbiter, as well as hosting the potential of a rich return in further science. SO/PHI measures the Zeeman effect and the Doppler shift in the FeI 617.3nm spectral line. To this end, the instrument carries out narrow-band imaging spectro-polarimetry using a tunable LiNbO_3 Fabry-Perot etalon, while the polarisation modulation is done with liquid crystal variable retarders (LCVRs). The line and the nearby continuum are sampled at six wavelength points and the data are recorded by a 2kx2k CMOS detector. To save valuable telemetry, the raw data are reduced on board, including being inverted under the assumption of a Milne-Eddington atmosphere, although simpler reduction methods are also available on board. SO/PHI is composed of two telescopes; one, the Full Disc Telescope (FDT), covers the full solar disc at all phases of the orbit, while the other, the High Resolution Telescope (HRT), can resolve structures as small as 200km on the Sun at closest perihelion. The high heat load generated through proximity to the Sun is greatly reduced by the multilayer-coated entrance windows to the two telescopes that allow less than 4% of the total sunlight to enter the instrument, most of it in a narrow wavelength band around the chosen spectral line.
description: 36 pages, 41 figures