External Colloquium - Gherardo Valori (MPS)

The Solar Orbiter Mission and the SO/PHI instrument: new opportunities for novel science

Solar Orbiter is a joint ESA-NASA mission that was launched in 2020 on a strongly eccentric orbit around the Sun, with closest perihelia at 0.28 AU. Solar Orbiter will reach up to 33 degrees heliographic latitude in the coming years. The Polarimetric and Helioseismic Imager is the vector magnetohraph onboard Solar Orbiter (SO/PHI), and it is composed of 2 telescopes: the Full-Disc Telescope (FDT) images the entire solar disk, while the High-Resolution Telescope (HRT) observes a smaller part of the solar disk at high resolution. SO/PHI typically provides maps of the continuum intensity, the magnetic field vector, as well as the LOS-velocity. High resolution observations are usually performed at dedicated orbital positions (perihelia, lowest and highest solar latitudes), whereas full disk observations are mostly obtained in a synoptic program outside these windows and on the far-side of the Sun.

The highly elliptic trajectory of Solar Orbiter allows for combining data from observatories in Near-Earth Orbit with observations taken from varying viewing angles outside the Sun-Earth line. Solar observations from different vantage points are already used in a variety of novel scientific applications, such as continuous monitoring of active regions across solar rotation, to produce synoptic magnetic field maps in as little as 14 days (under ideal conditions), and to test for the first time helioseismic measurements of active regions from far-side magnetograms. In addition, dedicated stereoscopic techniques are being developed that allow for the first time the purely observation-based removal of the 180-degrees ambiguity in vector magnetograms, as well as direct measurements of the Wilson depression in sunspots.

The forthcoming Photospheric Magnetic-field Imager (PMI) onboard ESA's Vigil will be the first space weather mission locating a spacecraft at the Lagrangian L5 point of the Sun-Earth system. PMI builds strongly on the heritage from SO/PHI, which then offers the opportunity to test under realistic conditions the quality of the data that PMI will produce, and to fine-tune PMI for monitoring the photospheric solar activity for space-weather applications.

• Date:
  April 25, 2024, 2 p.m. – 4 p.m.
  
  
• Location:

  Schwarzschild Haus Lecture Hall

  
  
• Contact:
  Julián Alvarado-Gómez