Speaker
Description
The nature of MHD waves within inhomogeneous media is fundamental to understanding and interpreting wave behaviour in the solar atmosphere. We investigate fast magnetoacoustic wave behaviour within magnetically-inhomogenous, gravitationally-stratified media, by studying various magnetic environments, including a simple X-type null point and also a topology created by two dipoles. We find that the addition of gravitational stratification fundamentally changes the nature of the system, including breaking the symmetry, and that that there are two main competing effects: the stratified-density profile acts in opposition to the strong magnetic field close to the dipoles, creating a system replete with refraction. The system is investigated using both numerical simulation and a semi-analytical WKB solution (via Charpit’s method and a fourth-order Runge-Kutta solver) and we find strong agreement between both. The results show a fundamental difference between the stratification-free and stratified cases, with significant unexpected behaviour, and we explain how these results fit into the pantheon of MagnetoAcousticGravity waves.
| Sessions | Wave generation, energy transport, dissipation and heating |
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