Solar Orbiter observes an active region on the Sun

The Sun seen by Solar Orbiter on 3 March 2022, during the spacecraft's first close approach to the Sun. This view was part of an important piece of research that opens up a new way for solar physicists to study the source regions of the solar wind.

The main, largest image was taken with the full Sun imager mode of Solar Orbiter's Extreme Ultraviolet Imager (EUI) instrument. The medium-sized image that appears after about five seconds was taken with EUI's high-resolution mode. The third, smallest image was taken with Solar Orbiter's Spectral Imaging of the Coronal Environment (SPICE) instrument.

The Sun's active regions are often responsible for solar flares and eruptions. Visual indicators of active regions are dark sunspots – cooler areas in the Sun's photosphere where intense magnetic fields become twisted and concentrated. The magnetic activity that creates sunspots is thought to be connected to the so-called ‘slow’ solar wind.

In this research, a team led by Stephanie Yardley from Northumbria University imaged an active region of the Sun with Solar Orbiter's EUI, SPICE and Polarimetric and Helioseismic Imager (PHI) instruments, before measuring the resulting slow solar wind with the spacecraft's in situ instruments several days later. This is the first ever connection between high-resolution images of the Sun’s surface at a close distance and direct measurements of the solar wind around a spacecraft. It allowed the scientists involved in the research to identify more clearly where the slow solar wind originates and opens up a new way for solar physicists to study the source regions of the solar wind.

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