Science

Here is the list of publications related to HESPE

It is now well accepted that of the different forms of solar activity, Coronal Mass Ejections (CMEs) control space weather and have the greatest effect on the Earth, both through their impact on the Earth’s magnetosphere and through the high energy particles that they accelerate as they propagate. But it is clear that solar flares and CMEs are intimately related. They generally occur together  and the CME acceleration phase is often coincident with the impulsive phase of the associated flare. The total energy dissipated in the largest flares is comparable to the total energy of the associated CMEs, known now very reliably from the increase in the total solar activity.

It is also well established that the total energy in flare-accelerated electrons as derived from X-ray observations is a large fraction of the total flare energy – on the order of 10% or more. The total energy in accelerated ions (from gamma-ray measurements) is comparable to the total energy in accelerated electrons. However, at the present time, many core aspects of the physical processes leading to the production of high-energy solar flare radiation still remain unclear. Principal among these are (i) the acceleration of the high-energy electrons and ions which produce the X- and gamma-ray radiation, i.e. , more specifically, how so many of these particles are accelerated so quickly to such high energies; and, (ii) the transport of these particles through the solar atmosphere and into interplanetary space. The dominant theoretical model for the production of flare X-rays, the so-called flare ‘standard model’, proposes a three-part process of particle acceleration (in the solar corona), transport, and radiation (primarily in the chromosphere), in which the electron acceleration and radiation regions are spatially separated, with an electron ‘beam’ transporting energy between the two. As observations, particularly in X-rays, have improved, this model has been challenged and alternatives proposed. Theoretical developments have proceeded in two main ways:

HESPE is working at important advances in scientific aspects involving: (i) advances in the theory of solar flare particle acceleration and transport (due to the availability of large databases of data analysed with the most powerful processing techniques); (ii) advances in solar physics as a whole (due to the greatly improved accessibility of the best X-ray data, from present and future missions, to the whole solar and heliospheric community, for easy integration into their ongoing analyses); (iii) better understanding of the sources of high energy particles escaping and transport from the Sun to the Earth, which is essential component of space weather.