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A Heuristic Approach to Remove the Background Intensity on White-light Solar Images. I. STEREO /HI-1 Heliospheric Images
Author | Stenborg, Guillermo; Howard, Russell; |
Keywords | methods: data analysis; parker solar probe; Solar Probe Plus; Sun: corona; Sun: coronal mass ejections: CMEs; techniques: image processing |
Abstract | White-light coronal and heliospheric imagers observe scattering of photospheric light from both dust particles (the F-Corona) and free electrons in the corona (the K-corona). The separation of the two coronae is thus vitally important to reveal the faint K-coronal structures (e.g., streamers, co-rotating interaction regions, coronal mass ejections, etc.). However, the separation of the two coronae is very difficult, so we are content in defining a background corona that contains the F- and as little K- as possible. For both the LASCO-C2 and LASCO-C3 coronagraphs aboard the Solar and Heliospheric Observatory (SOHO) and the white-light imagers of the SECCHI suite aboard the Solar Terrestrial Relationships Observatory (STEREO), a time-dependent model of the background corona is generated from about a month of similar images. The creation of such models is possible because the missions carrying these instruments are orbiting the Sun at about 1 au. However, the orbit profiles for the upcoming Solar Orbiter and Solar Probe Plus missions are very different. These missions will have elliptic orbits with a rapidly changing radial distance, hence invalidating the techniques in use for the SOHO/LASCO and STEREO/SECCHI instruments. We have been investigating techniques to generate background models out of just single images that could be used for the Solar Orbiter Heliospheric Imager and the Wide-field Imager for the Solar Probe Plus packages on board the respective spacecraft. In this paper, we introduce a state-of-the-art, heuristic technique to create the background intensity models of STEREO/HI-1 data based solely on individual images, report on new results derived from its application, and discuss its relevance to instrumental and operational issues. |
Year of Publication | 2017 |
Journal | The Astrophysical Journal |
Volume | 839 |
Number of Pages | 68 |
Section | |
Date Published | 04/2017 |
ISBN | |
URL | http://stacks.iop.org/0004-637X/839/i=1/a=68?key=crossref.646085eac9cc08a12f0de51ac7dce969 |
DOI | 10.3847/1538-4357/aa6a12 |