Remote Sensing of Gamma-Ray Emission from Solar Energetic Proton Interactions with the Solar Wind

This cartoon introduces a rather brilliant idea regarding solar energetic particles (SEPs) - a major component of some flares, traditionally called "proton flares". The idea is that the particles may be detectable remotely via interactions in the material of the solar wind that leads to gamma rays. This would be wonderful, if observable, since it would teach us about both SEPs and solar-wind dust. Note that the Fermi observations of high-energy γ rays from the solar direction have revealed a similar diffuse source, but attributed it to Compton scattering of relativistic cosmic-ray electrons on sunlight. The mechanism proposed here may not be so competitive observationally, and we should hope for future observations with enough sensitivity to see both. There would be a hopelessly undetectable polarization distinction, no doubt.

      Note an oddity about the cartoon: the flare location is shown as quite separate from the CME footpoints. This is probably an exaggeration.