New diagnostics of particle acceleration in solar coronal nanoflares from chromospheric observations and modeling


        Solar observations provide us with a close up view of fundamental physical processes at work in magnetized plasma, which are important on the Sun and in other astrophysical contexts. The proposed team will focus in particular on tackling the mechanisms converting magnetic energy into heating of the solar outer atmosphere and acceleration of particles, which are among the main open issues in solar physics.
        Recent observations with the Interface Region Imaging Spectrograph (IRIS) of small spatial and temporal scale brightenings at the footpoints (chromosphere and transition region) of solar coronal loops, combined with advanced radiation hydrodynamic modeling,have provided new diagnostics and significant new insights into the heating processes and mechanisms of energy transport across the different layers of the solar atmosphere (Testa et al., 2014). These findings have shown that the high resolution IRIS observations have the potential to provide tight constraints on the properties of small-scale heating events, on the presence and energy distribution of the non-thermal particles and on their importance in heating the non-flaring corona.
        We will determine the statistical properties of the observed spatial and temporal distribution of small-scale brightenings by analyzing chromospheric and TR observations of loop footpoint emission (IRIS), combined with coronal observations (Hinode/XRT and EIS, SDO/AIA). At the same time we will further develop the numerical models, focusing on including more realistic background atmosphere(s), as these play a critical role in determining the response of the plasma to impulsive heating events and the non-thermal particle properties.
        By comparing directly, in a quantitative fashion, the observations (in particular focusing on chromospheric and transition region emission) with the predictions of models of impulsively heated loops we will be able to investigate the prevalence and importance of non-thermal particles in non-flaring coronal plasma, and constrain the parameters of the non-thermal electron distribution.

example IRIS moss variability