Magnetic activity

Solar activity such as flares and the giant eruptions known as coronal mass ejections are driven by the Sun’s magnetism. The ESA/NASA Solar Orbiter spacecraft investigates the Sun’s magnetic field in a number of different ways, allowing it to trace the field from the Sun’s surface out into space.

These images were taken on 17 March 2022 by the Polarimetric and Helioseismic Imager (PHI) and Extreme Ultraviolet Imager (EUI) instruments. They show the same active region on the Sun.

The visible surface of the Sun is known as the photosphere. The PHI image (black and white) shows the magnetic polarity at the photosphere, where the Sun's magnetic field bursts upwards into the solar atmosphere. Black and white represent different magnetic polarity.

The EUI image (coloured) reveals the bright, one million degree-hot gas caught in the loops of magnetism that have broken through the photosphere and now reach into the atmosphere. Each footprint of the loop can be seen to have a different magnetic polarity. The EUI image also shows the ‘lace-like’ network of gas known as coronal moss. It was taken at a wavelength of 17 nanometers, in the extreme ultraviolet region of the spectrum, and has been colour-coded because this wavelength is invisible to the human eye.

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