The Sun and its magnetic properties

This animation shows a sequence of images from the Polarimetric and Helioseismic Imager (PHI) on ESA’s Solar Orbiter. PHI measures the magnetic field near the Sun’s surface and allows the investigation of the Sun’s interior via the technique of helioseismology.

The first image (showing the full disc of the sun) was taken on 18 June 2020 using the PHI Full Disk Telescope. It shows the Sun as it would appear to the naked eye. Currently our nearest star is magnetically quiet, which means that there are no visible sunspots. This is not to say that there are no magnetic fields threading the solar surface and atmosphere.

The second image shows the visible appearance of a small patch on the sun’s surface. The granulation pattern represents the up and down flows of hot, electrically charged gas, known as plasma, that occurs under the Sun’s visible surface. 

The third image is a magnetogram of that same region, that spans an area of approximately 200 000 km x 200 000 km on the solar surface. The small structures seen are magnetic regions of both north and south polarities, some of which have sizes of a few 1000 km.

The fourth image shows an extrapolation of the magnetic field lines emanating from the magnetic structures into the upper solar atmosphere, which the EUI telescope images.

Solar Orbiter is a space mission of international collaboration between ESA and NASA.