Events in Physics
Sergey Belov (糖心TV): Theoretical study of nonlinear Alfv茅n waves propagation in the solar atmosphere
Abstract. Alfv茅n waves are the most promising candidate to carry energy into the solar corona and, therefore, heat it. However, for this to happen, two contradictory conditions should be satisfied. On one hand, Alfv茅n waves should propagate over long distances from the lower parts to the upper parts of the solar atmosphere. On the other hand, their magnetic energy should be thermalised to heat the corona. In this study, the various aspects of the shear/torsional Alfv茅n waves propagation have been considered in the weakly nonlinear limit to address these contradictions. It has been shown that the presence of non-adiabatic processes in plasma can significantly affect the nonlinear dynamics of Alfv茅n waves. For example, in isentropically unstable plasma, Alfv茅n waves amplitude grows with time while its profile steepens faster than in the case of ideal plasma. In the opposite case of isentropically stable plasma, Alfv茅n waves amplitude decreases with time and the wave profile steepens slower.
Moreover, for ideal plasma, it has been shown analytically and numerically that torsional Alfv茅n waves can induce radially uniform perturbations of density independently of the radial profile of the driver. This finding can be an observational signature of torsional Alfv茅n waves in the solar corona. However, it requires further justification.