The U.S. National Science Foundation's Daniel K. Inouye Solar Telescope has captured the highest-resolution images ever taken of a solar flare at the H-alpha wavelength. The images, taken on August 8, 2024, reveal unprecedented detail of the Sun's coronal loops, with some structures as narrow as 21 kilometers.
These observations are a significant breakthrough in solar physics. They provide the first direct measurements of the fundamental scale of coronal loops, which are the building blocks of the Sun's magnetic architecture. This new data will allow scientists to refine their models of solar flares, leading to more accurate space weather forecasts. Improved forecasting is critical for protecting satellites, power grids, and communication systems on Earth from the disruptive effects of solar storms.
The images were captured during the decay phase of an X1.3-class solar flare. The Inouye Solar Telescope's ability to isolate the H-alpha wavelength, which is emitted by hydrogen atoms, allowed astronomers to see fine structures in the lower solar atmosphere that were previously unobservable. The discovery of these elementary structures opens up new avenues of research into the processes that drive solar flares, including magnetic reconnection.