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Dr David Kuridze from the Aberystwyth University’s Solar Physics Group (also a consultant for the Abastumani Astrophysical Observatory at Ilia State University) is a leading authority on the use of ground-based telescopes to study the Sun’s corona, the ring of bright light visible during a total eclipse.

Working from the Swedish 1-m Solar Telescope at Roque de los Muchachos Observatory, La Palma in the Canary Islands, Dr Kuridze studied a particularly strong solar flare which erupted near the surface of the Sun on 10 September 2017.

Writing in the journal Astrophysical Journal, Dr Kuridze reports on how a combination of favourable conditions and an element of luck enabled the team to determine the strength of the flare’s magnetic field with unprecedented accuracy.

Dr Kuridze believes the findings have the potential to change our understanding of the processes that happen in the Sun’s immediate atmosphere.

“Everything that happens in the Sun’s atmosphere is dominated by the magnetic field, but we have very few measurements of its strength and spatial characteristics”, Dr Kuridze said. “These are critical parameters, the most important for the physics of the solar corona. It is a little like trying to understand the Earth’s climate without being able to measure its temperature at various geographical locations.

This is the first time we have been able to measure accurately the magnetic field of the coronal loops, the building blocks of the Sun’s magnetic corona, which such a level of accuracy.”

The Sun’s corona

Measuring 1,400,000 kilometres across (109 times larger than Earth) and 150,000,000 kilometres from Earth, the Sun’s corona extends millions of kilometres above the surface.

Solar flares appear as bright flashes and occur when magnetic energy that has built up in the solar atmosphere is suddenly released.

Accurate measurement of the magnetic field is among major challenges in contemporary astrophysics due to the weakness of the signal from the Sun’s atmosphere that reaches Earth and carries information about the magnetic field.

The magnetic fields reported in this study are similar to those of a typical fridge magnet and around 100 times weaker than the magnetic field encountered in an MRI scanner. However, they are still responsible for the confinement of the solar plasma, which make up solar flares and coronal mass ejections.

Coronal mass ejections can lead to storms which, if they hit Earth, form the northern lights – the Aurora Borealis. They can also disrupt communications satellites and GPS systems, as proved to be the case on this occasion in September 2017. Furthermore, the altitude of flights over the polar-regions was restricted due to higher than normal radiation levels.

Dr Kuridze

Originally from the village of Nigzviani in Lanchkhuti Municipality of Guria, Georgia, Dr David Kuridze is a Sêr Cymru Fellow at the Department of Physics at Aberystwyth University. He also is a consultant for ISU Abastumani Astrophysical Observatory and Principal Investigator for Project FR17 323 supported by the Shota Rustaveli National Science Foundation.

Dr Kuridze is the lead author on Mapping the Magnetic Field of Flare Coronal Loops, which is published in the Astrophysical Journal, which also features Professors Teimuraz Zakarashvili and Vasil Kukhianidze of Ilia State University as co-authors.
Other co-authors on the paper represent Queens University Belfast, Universitat de les Illes Balears, Spain; University of Applied Sciences and Arts Northwestern Switzerland; Space Research Institute, Austrian Academy of Sciences, Austria; Astronomical Institute, Slovak Academy of Sciences; Institute for Solar Physics, Stockholm University, Sweden; Abastumani Astrophysical Observatory at Ilia State University, Georgia; IGAM, Institute of Physics, University of Graz, Austria; Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany.