MODELING MESOGRANULES AND EXPLODERS ON THE SOLAR SURFACE

Correlation tracking of high-resolution observations of solar granulation reveals a horizontal flow field containing both the supergranulation pattern and a much smaller pattern which corresponds to mesogranulation. Exploding granules (exploders) occur preferentially near the centers of mesogranules. This raises the question: are mesogranules just collections of exploders? Radial outflows in exploders and mesogranules can be modeled by superposing Gaussian source functions. This model is used to explore the relationship between mesogranules and exploders. Although we demonstrate that there is a mathematical equivalence between mesogranules and exploders distributed normally about the mesogranule centers, our results indicate that the observed mesogranular velocity pattern is not consistent with a flow pattern generated by exploders dropped randomly on the solar surface. Detailed comparisons with observations suggest that the averaged mesogranular velocity is produced by a combination of a persistent outflow from a source together with exploders distributed randomly about its center. Similar analysis also shows supergranules are not the result of random occurrences of mesogranules.