Search for nanoflare heating signatures in Hinode/XRT and SDO/AIA loops

M. LÓPEZ FUENTES; J. A. KLIMCHUK

St Andrews, Escocia

Congreso; Hinode-6 Meeting; 2012

It has been suggested (see Terzo et al. 2011, ApJ 736, 111) that certain statistical properties of intensity fluctuations in X-ray loops are consistent with the presence of impulsive heating. Here, we study the intensity evolution of a set of loop pixels from Hinode/XRT and SDO/AIA observations of active region NOAA 11147, obtained on January 18 2011. In search for possible signatures of nanoflare heating, we measure a series of statistical properties of the intensity fluctuations. We areparticularly interested in the skewness parameter, which determines the degree of asymmetry of the fluctuations distribution. This asymmetry may indicate the widespread presence of cooling processes in sub-resolution magnetic strands. We compare the above observations with the results of a 2D cellular automaton model based on nanoflare heating driven by photospheric motions. This model is a more sophisticated version of the one presented in Lopez-Fuentes & Klimchuk (2010, ApJ 719,591). We compute the plasma response to the nanoflare heating using the EBTEL code (see Klimchuk et al. 2008, ApJ 682, 1351), and from the known response of the instruments we construct syntheticlightcurves to compare with the observations. Our analysis shows that the observed and the model lightcurves have similar statistical parameters. We discuss the implications of these results for the coronal heating problem.