2021-05-20T10:27:37.000Z http://sot.lmsal.com Ted Tarbell LMSAL http://lmsal.com 3251 Hanover Rd, O/ADBS, B/252, Palo Alto, CA, 94304 +1-650-424-2400 tarbell@lmsal.com Hinode SOTSP Tezuka Brooks Tiwari (RCO) 417 417 null HOP 417 (GREGOR) 7-10UT CH CH Coronal Hole 16 548 -120 0 0 2021-05-20T06:50:30.000Z 2021-05-20T07:20:00.000Z 548 -120 Observation of small-scale structures in coronal holes with Hinode/EIS, IRIS & GREGOR Fast map, 123"x123", 1-side CCD Main Objective: The target of this study is the observation of small-scale structures with a full coverage by photospheric, chromospheric and coronal instruments. Scientific Justification: The key idea of this proposal is to improve the understanding of small-scale structures, which cause upflows in the solar corona. They are seen as small blue-shifts in Hinode/EIS data and show only small brightenings or faint eruptions in imaging data. The additional use of the ground-based GREGOR telescope will provide full coverage of those coronal features down till the photosphere. This could help to detect potential underlying mechanisms and their behaviour through different depths for individual events. The relevance of small features increased strongly after the discovery of campfires in Solar Orbiter EUI data and small fluctuations in the solar wind detected by Parker Solar Probe. This study will help to prepare for prospective combined observing missions with Solar Orbiter.