Solar flares as harbinger of new physics
  This work provides additional evidence on the involvement of exotic particles like axions and/or other WISPs, following recent measurements during the quietest Sun and flaring Sun. Thus, SPHINX mission observed a minimum basal soft X-rays emission in the extreme solar minimum in 2009. The same scenario (with ~17 meV axions) fits also the dynamical behaviour of white-light solar flares, like the measured spectral components in the visible and in soft X-rays, and, the timing between them. Solar chameleons remain a viable candidate, since they may preferentially convert to photons in outer space. 
K. Zioutas, M. Tsagri, Y. Semertzidis, T. Papaevangelou, E.   Georgiopoulou, A. Gardikiotis and T. Dafni
astro-ph.SR