'Nanoflares' maybe responsible for sun's coronal heating

Scientists have studied the mystery of 'nanoflares' that may be responsible for causing coronal heating in the Sun and these observations were used from the recently launched Interface Region Imaging Spectrograph (IRIS).

The team led by Paola Testa of the Harvard-Smithsonian Center for Astrophysics (CfA) found that the 'nanoflares' produced speedy electrons, which were about a billion times less energetic than regular solar flares. These nanoflares, as well as the energetic particles associated with them, were difficult to study because they couldn't observe them directly but these particles might partly be the source of that heat, at least in some of the hottest parts of the Sun's corona.

The scientist suggested that a solar flare occurred when a patch of the Sun brightened dramatically at all wavelengths of light. During flares, solar plasma was heated to tens of millions of degrees in a matter of seconds or minutes. Flares also could accelerate electrons (and protons) from the solar plasma to a large fraction of the speed of light.

These high-energy electrons could have a significant impact when they reach Earth, causing spectacular 'aurorae' but could also disrupting communications, affecting GPS signals, and damaging power grids.

Finding the high-energy electrons that aren't associated with large flares suggested that the solar corona was, at least partly, heated by 'nanoflares'and the observations, combined with computer modeling, also helped astronomers to understand how electrons were accelerated to such high speeds and energies, a process that played a major role in a wide range of astrophysical phenomena from cosmic rays to supernova remnants.

These findings also indicated that 'nanoflares' were powerful, natural particle accelerators despite having energies about a billion times lower than large solar flares.