Multi-view magnetic synoptic maps with SO/PHI and SDO/HMI

Abstract:

With the recent launch of Solar Orbiter (SO) and the first data slowly becoming available, it will soon be possible to simultaneously observe the Sun from additional vantage points off the Earth-Sun line. One of its instruments, the Polarimetric and Heliospheric Imager (PHI), is the first spectro-polarimeter to operate outside of this line of sight. This opens the possibility for joint observational campaigns with similar instruments, such as the Heliospheric and Magnetic Imager (HMI) on-board the Solar Dynamics Observatory (SDO). We utilise these new observational possibilities to produce combined magnetic synoptic maps from magnetograms of the PHI and HMI instruments. Building on the existing software infrastructure for HMI synoptic maps, we extended its current functionality to include PHI data and correct for the different and varying relative orbital characteristics of the two spacecraft. The result are joint magnetic synoptic maps, that can be produced significantly faster than the approximately 27 days of one solar rotation and therefore are less likely to suffer from the evolution of the magnetic field over the observation period. Once Solar Orbiter leaves the ecliptic plane, we will also be able to include observations of the polar magnetic field into our synoptic maps, which will give an unprecedented insight into the magnetic field of the Sun. This work presents our preparatory modelling efforts and gives an outlook for the future capabilities of this novel data product.