Radio waves are providing a new way to probe the Sun and suggest that the magnetic field of its corona may be stronger than long thought
At about the same time the Sun was blowing off the largest flare measured in over a decade, the strength of the magnetic field in its atmosphere hit a record high.
But that may not be abnormal. New research suggests that the Sun’s magnetic field may climb to levels of intensity stronger than currently predicted, a discovery that could have implications for the effects of solar weather on Earth’s technology and infrastructure.
On 6 September 2017, solar astronomers identified a massive X9.3 flare exploding outward from a preexisting sunspot. X describes the most intense class of flare, while the associated number relates to its strength. Most flares are classified between 1 and 9.
The entire area where the X9.3 flare took place had been classified as an active region, where the strongest large-scale magnetic fields are concentrated on the Sun. The Sun also released several other powerful solar flares during the same month, many of them stemming from the same area.“The magnetic field might be stronger than people have been thinking about.”“It was a very interesting active region,” said Gregory Fleishman, a heliophysicist at the New Jersey Institute of Technology in Newark.
Fleishman was part of a research team that captured measurements of the coronal magnetic field, a historically challenging part of the Sun to study. By probing the field in radio wavelengths and comparing their findings to historical observations, the team discovered that the coronal magnetic field may be more powerful than previously expected.
The team’s findings, along with its technique, may allow researchers to improve understanding of what’s happening in the solar atmosphere and how it could affect Earth. Results were published in August in the Astrophysical Journal Letters.
“The magnetic field might be stronger than people have been thinking about,” Fleishman said. “There might be more energy to drive extreme [space] weather.”