Evolution of a solar campfire and its magnetic field lines as generated in a computer simulation. ‘Campfires’ are miniature solar flares discovered by ESA’s Solar Orbiter mission in 2020.

In both images the left panel shows a simulated view of emission from the Sun’s corona, as would be seen by Solar Orbiter’s Extreme Ultraviolet Imager. The right panel shows the corresponding magnetic field as a magnetogram, where black and white are opposite polarities, and grey is zero field. Overplotted on the magnetogram are selected field lines in different colours.

At first, field lines from the bottom-right white magnetic patch are seen stretching up to the top left. In the second part these field lines have been “eaten-up” by reconnection, a process whereby field lines break and then reconnect, releasing energy when they do so.

Modelling shows that the energy released from the brightenings throughcomponent reconnection may be enough to maintain the temperature of the solar corona predicted from observations.