June 5 (UPI) -- Astronomers have successfully measured the shape of the magnetic field in the solar corona, the outermost layer of the sun's atmosphere.
Solar winds, streams of high-energy particles, radiate from the sun's outer atmosphere. To understand space weather, scientists must understand the corona.
More powerful space observatories and advances in telescope instrument technology have helped scientists study the complexities of the sun's atmosphere, but some solar phenomena can only be observed during a solar eclipse.
Using detailed observations of the corona, captured by telescopes during more than a dozen solar eclipses, scientists produced a large, high-resolution map of coronal magnetic field.
Scientists detailed the mapping effort this week in the Astrophysical Journal.
"The corona has been observed with total solar eclipses for well over a century, but never before had eclipse images been used to quantify its magnetic field structure," lead author Benjamin Boe, graduate student at the University of Hawaii Institute for Astronomy, said in a news release. "I knew it would be possible to extract a lot more information by applying modern image processing techniques to solar eclipse data."
Boe mapped the distribution of magnetic field lines revealed by observations captured during 14 different solar eclipses over the last 20 years. The mapping effort revealed highly structured patterns of magnetic fields.
The data also showed the corona's magnetic field patterns shift over the course of the sun's 11-year solar cycle.
During periods of limited solar activity, the corona's magnetic field lines emerge at right angles, streaming directly out from the equator and poles. Field lines emanating from the mid-latitudes adopt a wider variety of angles.
When solar activity spikes, the corona's magnetic field lines become more radial and less structured, spewing out in a variety of directions.
"We knew there would be changes over the solar cycle, but we never expected how extended and structured the coronal field would be," Boe said. "Future models will have to explain these features in order to fully understand the coronal magnetic field."
The new research could help scientists better understand the formation of solar winds, as well as the mechanisms that govern the trajectory of space weather once it leaves the sun's atmosphere.
"These results are of particular interest for solar wind formation. It indicates that the leading ideas for how to model the formation of the solar wind are not complete, and so our ability to predict and defend against space weather can be improved," said Boe.