The Sun’s magnetic field is ten times stronger than previously believed, according to a study of a particularly strong solar flare that erupted near the sun’s surface in September of 2017.
The new study, conducted by Queen’s University Belfast and Aberystwyth University, took advantage of a combination of favorable conditions and an element of luck that allowed the team to determine the strength of the magnetic field of a solar flare with unprecedented precision, thanks to the Swedish 1-m Solar Telescope at Roque de Los Muchachos Observatory, La Palma in the Canary Islands.
The researchers, led by David Kuridze—a leading scientist in the use of ground-based telescopes to study the solar corona—believe that the findings have the potential to change our understanding of the processes that occur in the immediate atmosphere of the sun.
Writing in the journal Astrophysical Journal, Dr. Kuridze reports on how a combination of favorable conditions and an element of luck enabled the team to determine the strength of the flare’s magnetic field with unprecedented accuracy.
“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 explained.
“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 the magnetic field of the coronal loops, the building blocks of the Sun’s magnetic corona, with such a level of accuracy,” Dr. Kuridze added.
Measuring a mind-bending 1,400,000 kilometers across (109 times larger than Earth) and 150,000,000 kilometers from Earth, the Sun’s corona extends millions of kilometers above the surface.
When studying the sun, solar flares appear as bright flashes and occur when the magnetic energy that has accumulated in the sun’s atmosphere is suddenly released.
Until now, the successful measurement of the magnetic field has been hampered by the weakness of the signal from the solar atmosphere that reaches the Earth and the limitations in the available technology.
The magnetic field readings, reported in the new stud were found to be similar to those of a typical fridge magnet and around 100 times weaker than the magnetic field encountered in an MRI scanner.
As noted by a statement from the Aberystwyth University, “they are still responsible for the confinement of the solar plasma, which make up solar flares, as far as 20,000 km above the Sun’s surface.”
Professor Michail Mathioudakis from the School of Mathematics and Physics, Queen’s University Belfast, who also worked on the project, added: “This is a unique set of observations that, for the first time, provide a detailed map of the magnetic field in coronal loops.
“This highly rewarding result was achieved due to the dedication and perseverance of our early career scientists who planned and executed the observations. The methodology used in this work and the result itself will open new avenues in the study of the solar corona.”