Low-frequency waves and turbulence in an open magnetic region: Timescales and heating efficiency

Low-frequency Alfven waves injected in an open magnetic region from the bottom propagate and transport the energy upward. Wave reflections due to background inhomogeneities activate a nonlinear turbulent energy transfer to small scales, perpendicular to the main field direction, which enhance energy deposition within the region. A dynamically rich situation is established, in which different timescales are at play, and they determine the efficiency on dissipating the injected energy. In this paper, we identify the relevant timescales of the system and propose an ordering that favors the turbulent dissipation. It is shown that even cases of relatively a low amount of reflected waves can be efficient enough for dissipating energy. We have previously applied this mechanism for the heating of the lower corona required in models of the origin of the solar wind.