The radial outflows in sunspot penumbrae, known as the Evershed effect, are of significant interest for understanding the dynamics of sunspots. Local helioseismology has not been able to determine the depth of these flows nor their relationship to mass circulation in sunspots. Recent radiative MHD simulations have provided a convincing explanation of the Evershed flow as a natural consequence of magnetoconvection in the strongly inclined magnetic field region of the penumbra. The simulations reproduce many observational features of penumbra dynamics, including the filamentary structure, the high-speed non-stationary "Evershed clouds", and the "sea-serpent" behavior of magnetic field lines. We present the subsurface structure of the Evershed effect, obtained from numerical simulations, and determine the depth of the radial outflows for various magnetic field strengths and inclinations. The simulations predict that Evershed flows are rather shallow and concentrated in the top 0.5 - 1 Mm layer of the convection zone. This prediction can be tested by local helioseismology methods.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)