Study of Type III Radio bursts in the Closed Corona and the Solar Wind from Small-scale Reconnection: Observations

It is widely agreed that the ubiquitous presence of reconnection events and the associated impulsive heating (nanoflares) are a strong candidate for heating the magnetically closed corona. Whether nanoflares accelerate energetic particles like fullsized flares is unknown. The lack of strong emission in hard Xrays suggests that the quantity of highly energetic particles is small. There could, however, be large numbers of mildly energetic particles (~ 10 keV). Similarly, in the context of the solar wind, these energetic particles can originate from interchange reconnection, streamer tip reconnection, or turbulence reconnection in the solar wind itself, in which case they stream away from the Sun along the open field lines. To understand whether these processes are efficient at accelerating particles, we search for the type III radio bursts that they may produce. The timelag technique that was developed to study subtle delays in light curves from different EUV channels [Viall & Klimchuk 2012] can also be used to detect subtle delays at different radio frequencies. We have modeled the expected radio emission from mildly energetic particles propagating in the closed corona and open corona/solar wind. The models were used to test and calibrate the technique. We are currently applying the technique to radio observations from VLA (Very Large Array), LOFAR (LowFrequency Array), LWA, NM (Long Wavelength Array, New Mexico), and the FIELDS experiment (encounters 1-6) to search for such signatures of type IIIs. We also plan to investigate the relationship between the bursts and activity on the Sun, such as the presence/absence of active regions, relationship with their age etc. We will report the results from our analysis.