Flare Primary Energy Site

The solar x-ray images are from the Yohkoh mission of ISAS, Japan. The x-ray telescope was prepared by the Lockheed Palo Alto Research Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo with the support of NASA and ISAS.

Caption:

• The top row of images is the first direct proof that the primary energy source for flares lies above the soft xray loops. The images were taken by the Yokhoh spacecraft and show soft xrays in color and hard xray contours during a flare event on the limb. It is clear that the contours of hard xrays are centered above the maximum soft xray emissions.
• The diagram to the left shows the major energetic mechanisms during the flare event which takes place within a single isolated coronal loop.
  • The primary energy release triggers the flare event during which electrons and protons are accelerated rapidly to speeds approaching the speed of light.
  • High energy electrons emit radiation at radio wavelengths near the top of the loop.
  • High energy particles create xrays and gamma rays as a result of bremsstrahlung when they impact the relatively denser chromosphere
  • Energetic neutrons and gamma rays are created as high-energy electrons penetrate the dense lower atmosphere.
  • A rapid rise in heating at the footpoints creates an explosive rise of heated chromospheric material to fill the loop. This material emits soft xray radiation and outlines the post-flare loop structure.