Sunspot Simulations: Penumbra Formation and the Fluting Instability
- 1 February 2021
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 907 (2), 102
- https://doi.org/10.3847/1538-4357/abccbf
Abstract
The fluting instability has been suggested as the driver of the subsurface structure of sunspot flux tubes. We conducted a series of numerical experiments where we used flux tubes with different initial curvatures to study the effect of the fluting instability on the subsurface structure of spots. We used the MURaM code, which has previously been used to simulate complete sunspots, to first compute four sunspots in the slab geometry and then two complete circular spots of opposite polarities. We find that the curvature of a flux tube indeed determines the degree of fluting the flux tube will undergo-the more curved a flux tube is, the more fluted it becomes. In addition, sunspots with strong curvature have strong horizontal fields at the surface and therefore readily form penumbral filaments. The fluted sunspots eventually break up from below, with lightbridges appearing at the surface several hours after fluting commences.Funding Information
- European Research Council (695075)
This publication has 16 references indexed in Scilit:
- ANALYSIS OF A FRAGMENTING SUNSPOT USINGHINODEOBSERVATIONSThe Astrophysical Journal, 2012
- NUMERICAL SUNSPOT MODELS: ROBUSTNESS OF PHOTOSPHERIC VELOCITY AND MAGNETIC FIELD STRUCTUREThe Astrophysical Journal, 2012
- SUBSURFACE MAGNETIC FIELD AND FLOW STRUCTURE OF SIMULATED SUNSPOTSThe Astrophysical Journal, 2011
- PENUMBRAL FINE STRUCTURE AND DRIVING MECHANISMS OF LARGE-SCALE FLOWS IN SIMULATED SUNSPOTSThe Astrophysical Journal, 2011
- Modeling the Subsurface Structure of SunspotsSolar Physics, 2010
- Penumbral Structure and Outflows in Simulated SunspotsScience, 2009
- RADIATIVE MAGNETOHYDRODYNAMIC SIMULATION OF SUNSPOT STRUCTUREThe Astrophysical Journal, 2009
- Simulations of magneto-convection in the solar photosphereAstronomy & Astrophysics, 2004
- The Theory of SunspotsPublished by Springer Science and Business Media LLC ,1992
- Sunspots and the physics of magnetic flux tubes. I - The general nature of the sunspot. II - Aerodynamic dragThe Astrophysical Journal, 1979