Asymmetric twisting of coronal loops

The bright solar corona entirely consists of closed magnetic loops rooted in the photosphere. Photospheric motions are important drivers of magnetic stressing which eventually leads to energy release into heat. These motions are chaotic and obviously different from one footpoint to the other, and in fact there is strong evidence that loops are finely stranded. One may also expect strong transient variations along the field lines, but at glance coronal loops ever appear more or less uniformly bright from one footpoint to the other. We investigate this issue by time- dependent 2.5D MHD modeling of a coronal loop including its rooting and beta-variation in the photosphere. We assume that the magnetic flux tube tube is stressed by footpoint rotation but also that the rotation has a different pattern from one footpoint to the other. In this way we force strong asymmetries, because we expect independent evolution along different magnetic strands. We show here preliminary results, which seem to indicate an important role of the time scales involved.