Speaker
Description
Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere and are key in many models for seismological or energy conversion processes. Metis has observed such waves too thanks to its unprecendented cadence. Using MHD simulations, we study wave propagation in a helmet streamer. Our model includes important physics such as spherical expansion, gravitational stratification, thermal conduction, radiative cooling, and a background wind. The magnetic field configuration associated with a helmet streamer not only provides opportunities for wave dissipation in open and closed field regions, but also at the interface of the two. In all cases, wave dissipation can happen via phase mixing, which, in conjunction with ponderomotive forces due to non-linear waves, can perturb the local density and temperature.
We compare the density variations of our model with observations of Metis in order to diagnose the mechanisms that lead to the observed progation of waves in streamers and pseudostreamers and into the solar wind.
