Speaker
Description
Recent simulations and observations often show Alfvén waves in the solar atmosphere with sufficient power to heat the solar corona and accelerate the solar wind. It is long been accepted that low-frequency Alfvén waves are suppressed due to inhomogeneities and steep spatial gradients in the solar atmosphere, with high-frequency waves being rapidly damped in the solar atmosphere. The effect of the rate of field line expansion on Alfvén wave propagation across the frequency spectrum is largely unexplored. We present evidence that certain expansion factors may significantly enhance the energy flux of Alfvén waves that reach the solar corona. We investigate the temporal evolution of periodic and randomly driven Alfvén waves propagating along field lines of different expansion rates in a stratified solar atmosphere. Numerical techniques are employed in the simulation to solve the linearised equations of motion and induction, and the resulting energies and power spectra at the transition region are calculated for the different expansion rates.
