SOHO CoRoT Kepler Picard SDO GONG

An Introduction to Wave Trapping in Supergranulation


Allen Walter


National Solar Observatory/GONG Program


Convection, dynamo and flows
Auteur(s) supplémentaire(s)Dr. Frank Hill
Institution(s) supplémentaire(s)National Solar Observatory


In this paper we solve a PDE (partial differential equation) having
the form of a wave equation that will be used to model waves trapped in a supergranule. The shape of the
supergranule is in the form of a hexagon and the model resulting from it is
found by taking advantage of boundary conditions. Also the solution found for
the PDE is done analyticaly and gravitational stratification, pressure
gradients and magnetohydrodynamic effects are currently omitted (although we
eventually will account for these phenomena as our model evolves). As we
include non-homogeneous terms through gravity, pressure, and other
perturbations, we may solve the PDE numerically through finite difference

There are various questions we will seek to answer by comparing the model to HMI (Helioseismic
Magnetic Imager) data. Specifically we hope to eventually answer three questions.
First can we determine whether supergranules are
directly convective or if they convect through smaller constructs that make up the supergranule? Secondly can we determine or get a better estimate of the depth of supergranules? Finally, can we obtain a better
understanding of the fluid flow inside the supergranule? Another aspect of this study involves accounting for the behaviour of
the magnetic field directly beneath
supergranulation. As field lines rise through the photosphere, and as active regions are formed, we may eventually find a way to account for the solar dynamo.
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