Mathematicians at Durham University are helping to unravel the knotty problem of how solar energy is injected into the Sun’s atmosphere before being released into space.
The release of this solar energy causes space weather events and there has been a longstanding debate about how this happens.
Now a team of researchers, including Dr Christopher Prior in Durham’s Department of Mathematical Sciences, has devised a new approach to analysing how the magnetic tangles of the Sun develop.
Their studies indicate that pre-twisted magnetic fields rise up from the Sun’s convection zone, which could lead to events such as solar flares.
Dr Prior, who worked alongside colleagues from the University of Glasgow and INAF-Osservatorio Astrofisico di Catania, in Italy, will present the findings today (Thursday 22 July) at the Royal Astronomical Society’s virtual National Astronomy Meeting (NAM 2021).
Researchers generally agree that solar activity is caused by instabilities in giant twists of magnetic ropes threading the visible surface of the Sun, known as the photosphere.
However, there has been an ongoing debate about how these tangles form. The two dominant theories have suggested either that coils of field lines emerge through the photosphere from the convection zone below, or that the feet of arching field lines wrap around each other on the surface itself and create braids.
Both mechanisms could theoretically produce effects like sunspot rotation and dramatic solar flares, but to date no direct observational evidence had conclusively supported either scenario.
Dr Prior and colleagues came up with a new direct measure of the entanglement of the magnetic field by tracking the rotation of field lines at the points where they intersect with the photosphere.
This “magnetic winding” should show in different ways for each of the two theories. Therefore, applying magnetic winding to observations of the photosphere and examining the resulting patterns could provide a definitive answer to show which theory is correct.
The researchers studied the magnetic winding for ten active regions on the Sun in observations by NASA’s Solar Dynamics Observatory, the European Space Agency’s Solar Orbiter and the Daniel K Inouye Solar Telescope (DKIST) in Hawaii.
In every case, the results matched the emergence theory of pre-twisted magnetic field lines rising up from the convection zone.
Dr Christopher Prior, in Durham University’s Department of Mathematical Sciences, said: “The pattern for pre-twisted field lines exactly matched the observational data we considered initially, and this has since been found to be true for all data sets of active regions we have looked at so far.
“We anticipate that magnetic winding will become a staple quantity in the interpretation of magnetic field structure from observational data.”
News source: Durham University.