Observational Signatures of Impulsively Heated Coronal Loops: Power-Law Distribution of Energies

It has been established that small scale heating events, known as nanoflares, are important for solar coronal heating if the power-law distribution of their energies has a slope α steeper than −2 ( α <−2). Forward modeling of impulsively heated coronal loops with a set of prescribed power-law indices α is performed. The power-law distribution is incorporated into the governing equations of motion through an impulsive heating term. The results are converted into synthetic Hinode /EIS observations in the 40″ imaging mode, using a selection of spectral lines formed at various temperatures. It is shown that the intensities of the emission lines and their standard deviations are sensitive to changes in α . A method based on a combination of observations and forward modeling is proposed for determining whether the heating in a particular case is due to small or large scale events. The method is extended and applied to a loop structure that consists of multiple strands.