Decayless Kink Oscillations Excited by Random Driving: Motion in Transitional Layer

Abstract In this article we study the plasma motion in transitional layer of a coronal loop randomly driven at one its footpoints thin-tube and thin-boundary-layer (TTTB) approximation. We introduce average square random function with respect to time. This can be considered as oscillation amplitude quantity. Then calculate amplitudes radial azimuthal displacement well perturbation magnetic pressure. find that magnetic-pressure do not change across layer. The is same order driver amplitude. times ratio radius length squared. $\text{Re}^{1/6}$ Re 1 / 6 , where Re Reynolds number. It has peak position local Alfvén frequency coincides fundamental kink oscillation. near far from it $\ell$ ? thickness radius. dependence on distance particular case density profile linear.