Astronomers in New York witnessed a unique and stunning event on Monday as massive, translucent plasma loops rose above the surface of the sun following a powerful solar flare. These ethereal remnants, known as post-flare loops (PFLs), remain a mystery to scientists who are still trying to understand how they form.
The solar flare, which registered at a powerful 6.8 magnitude M-class, erupted from sunspot AR3559 as it began to disappear behind the sun’s western limb. This phenomenon led to the creation of large loops of ionized gas, or plasma, above the sun’s surface. These loops, also known as prominences, are held in place by the magnetic field lines of dark-colored sunspots. Eventually, they snap like an elastic band as solar flares explode, launching the looped plasma into space as a coronal mass ejection (CME).
Images captured by astrophotographer Eduardo Schaberger Poupeau showed the faint plasma loops towering above the solar surface, where the CME had erupted from. These loops are puzzling as all the plasma from the area should have theoretically been ejected into space as a CME. The structures are only visible when the sun is viewed with a special filter that enhances red wavelengths of light given off by hydrogen, known as H-alpha, according to NASA.
Despite being documented frequently by researchers, there is still some confusion about how PFLs form. Researchers initially believed that the plasma comes from the solar surface and fills in the magnetic field lines after they recover from snapping. However, more recent observations suggest the magnetic loops may actually be pulling back some of the plasma that has been ejected into space by solar flares, according to Spaceweather.com.
As the sun nears the explosive peak in its roughly 11-year solar cycle, known as the solar maximum, the frequency and power of solar flares are rapidly increasing. This means that there will be many more PFLs over the coming years, providing an opportunity for scientists to gain a deeper understanding of how they form. With the increasing solar activity, there is an opportunity for more observations and studies, shedding light on this mysterious process.