SUBSURFACE MAGNETIC FIELD AND FLOW STRUCTURE OF SIMULATED SUNSPOTS
- High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States)
We present a series of numerical sunspot models addressing the subsurface field and flow structure in up to 16 Mm deep domains covering up to two days of temporal evolution. Changes in the photospheric appearance of the sunspots are driven by subsurface flows in several Mm depth. Most of magnetic field is pushed into a downflow vertex of the subsurface convection pattern, while some fraction of the flux separates from the main trunk of the spot. Flux separation in deeper layers is accompanied in the photosphere with light bridge formation in the early stages and formation of pores separating from the spot at later stages. Over a timescale of less than a day we see the development of a large-scale flow pattern surrounding the sunspots, which is dominated by a radial outflow reaching about 50% of the convective rms velocity in amplitude. Several components of the large scale flow are found to be independent from the presence of a penumbra and the associated Evershed flow. While the simulated sunspots lead to blockage of heat flux in the near surface layers, we do not see compelling evidence for a brightness enhancement in their periphery. We further demonstrate that the influence of the bottom boundary condition on the stability and long-term evolution of the sunspot is significantly reduced in a 16 Mm deep domain compared to the shallower domains considered previously.
- OSTI ID:
- 21587431
- Journal Information:
- Astrophysical Journal, Vol. 740, Issue 1; Other Information: DOI: 10.1088/0004-637X/740/1/15; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
BOUNDARY CONDITIONS
CONVECTION
EVOLUTION
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
PHOTOSPHERE
SIMULATION
STABILITY
SUNSPOTS
ATMOSPHERES
ENERGY TRANSFER
FLUID MECHANICS
HEAT TRANSFER
HYDRODYNAMICS
MASS TRANSFER
MECHANICS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
STARSPOTS
STELLAR ACTIVITY
STELLAR ATMOSPHERES