Description
Observationally, localized strengthening of the f mode is known to precede the emergence of solar active regions by up to 48 hours. Similar effects have been found in simplified numerical models. For the first time, we have been able to demonstrate such effects in a 3D simulation of convection. While a magnetic field near the top of the convection zone (CZ) strengthens the f mode, a magnetic field of equal strength near the bottom of the CZ produces a much weaker effect. I will also talk about how unresolved small-scale magnetic fields can be probed using local helioseismology. If time permits, I will also demonstrate the effect of internal reflection on the number of radial nodes of the p mode. This resolves a long-standing disagreement between simulations, where it has been reported that the lowest p mode has zero radial nodes, and observations, where the lowest p mode is thought to have one radial node.
