A nanoflare based cellular automaton model and the observed properties of the coronal plasma

TL;DR

This study employs a cellular automaton model based on nanoflares to simulate coronal loop plasma evolution, successfully reproducing observed intensity fluctuations, plasma cooling signatures, and emission measure distributions in active region loops.

Contribution

The paper introduces a nanoflare-based cellular automaton model that accurately replicates key observational properties of coronal plasma evolution in active regions.

Findings

Model reproduces observed intensity fluctuation amplitudes of 10-15%.

Intensity distribution skewness indicates cooling plasma presence.

Predicted emission measure slopes align with observational data.

Abstract

We use the cellular automaton model described in L\'opez Fuentes \& Klimchuk (2015, ApJ, 799, 128) to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active region (AR) observations obtained with the Hinode/XRT and SDO/AIA instruments. The comparison is based on the statistical properties of synthetic and observed loop lightcurves. Our results show that the model reproduces the main observational characteristics of the evolution of the plasma in AR coronal loops. The typical intensity fluctuations have an amplitude of 10 to 15\% both for the model and the observations. The sign of the skewness of the intensity distributions indicates the presence of cooling plasma in the loops. We also study the emission measure (EM) distribution predicted by the model and obtain slopes in log(EM) versus log(T) between 2.7 and 4.3, in agreement with published observational values.