A 15-minute flight launched on Dec. 11, 2014 was the second iteration of the FOXSI experiment. Although it only collected six minutes of data, FOXSI achieved its goal. The instrument detected hard X-rays, the most energetic light still within the X-ray range. The presence of hard X-rays suggests the presence of extremely hot material associated with solar flares.
Additional data from the JAXA and NASA Hinode solar observatory, which orbits above Earth in almost continuous daylight, enabled scientists to pinpoint the spot on the sun that these X-rays came from. Since no flares were observed in this region from Earth, the material was likely produced by a series of nanoflares, according to the NASA statement.
“There’s basically no other way for these X-rays to be produced, except by plasma at around 10 million degrees Celsius [18 million degrees Fahrenheit],” said Steve Christe, the project scientist for FOXSI at NASA’s Goddard Space Flight Center. “This points to these small energy releases happening all the time, and if they exist, they should be contributing to coronal heating.”
Astrophysicists still want to determine how much energy these nanoflares actually release, and to determine the mechanisms by which they work. For that, Glesener is leading an effort to launch a third FOXSI experiment on a sounding rocket in the summer of 2018. The next iteration will filter out more background noise to allow even more precise measurements.