ESA Science & Technology - Footprint of the solar wind

One of the principal goals of Solar Orbiter is to understand how the Sun is connected to interplanetary space. This connection takes place via the Sun’s magnetic field and the solar wind. The Sun’s magnetic field stretches through space, around Earth and the other planets, to create the heliosphere. The solar wind is the constant stream of particles that flows away from the Sun.

Solar Orbiter’s goal is to link the solar wind flowing past the spacecraft with a source region or ‘footprint’ on the Sun. This will show how and where that specific section of the wind is generated.

This movie shows the calculated source region of the solar wind that subsequently flowed past Solar Orbiter. The movie has been constructed from images taken by the Extreme Ultraviolet Imager (EUI) instrument on Solar Orbiter between 17 and 21 June 2020. The green cross is the region calculated to be responsible for the solar wind that’s hitting Solar Orbiter. The movie shows how the footprint moves with time. It is notable that the footprint is always located at the edge of a region called a ‘coronal hole’, seen here as a dark patch on the surface of the Sun. A coronal hole is where the Sun’s magnetic field reaches out into space, and this allows the solar wind to flow.

Mapping of this accuracy has never been possible before and as Solar Orbiter goes closer to the Sun, so the detail will only increase.