| Presenter: | Silvano Fineschi |
| Affiliation: | INAF-Osservatorio Astronomico di Torino |
| Title: | Space-based solar polarimetry |
| Authors: | S. Fineschi, and the COMPASS Team |
| Form: | invited |
| Abstract: | The high-temperature (10$^4$--10$^7$~K) plasmas in the solar atmosphere has strong emissions in the ultraviolet (UV) wavelength region (10$^2$~nm). Spectro-polarimetric UV observations from space of these emissions, interpreted in terms of the Zeeman and the Hanle effects, are a powerful tool for the diagnostics of magnetic fields in the solar chromosphere/corona. The past and current status of instrumentation and observing techniques for space UV polarimetry are reviewed. The future prospectives are also discussed of new space instruments and missions for solar UV polarimetry. A mission for coronal magnetism, plasma and activity studies from space (COMPASS) has been recently proposed in response to the ESA Announcement of Opportunity for the 2015--2025 Cosmic Vision Programme. COMPASS will take a multipronged approach to measure the weak (1--100 G) coronal field. It will record the Hanle as well as the Zeeman effect, both of which influence the polarization in UV spectral lines. In addition, it will also observe highly ionized spectral lines in the infrared (IR) solar spectrum and visible lines at the solar surface in order to get a complete picture of the field. The mission implementation will be presented consisting of two formation flying spacecrafts in halo orbit around Lagrange Point 1 of the Sun-Earth system. The payload-carrying spacecraft is partially occulted by the ``occulter spacecraft (S/C)'' that flies about 100~m ahead, in the Sun’s direction. The ``occulter S/C'' provides the necessary occultation to the coronagraphs, while leaving an unobstructed view to the on-disk instruments. |
| Session: | 6. Coronal radio and infrared polarimetry |
| Presentation date: | Wednesday 19th September |
| Presentation time: | 12:00:00 |