Evershed and Counter-Evershed Flows in Sunspot MHD Simulations
نویسندگان
چکیده
منابع مشابه
Convection and the Origin of Evershed Flows in Sunspot Penumbrae
We discuss a numerical 3D radiation-MHD simulation of penumbral fine structure in a small sunspot. This simulation shows the development of short filamentary structures with horizontal flows, similar to observed Evershed flows, and an inward propagation of these structures at a speed compatible with observations. Although the lengths of these filaments are much shorter than observed, we conject...
متن کاملConvection and the Origin of Evershed Flows
Numerical simulations have by now revealed that the fine scale structure of the penumbra in general and the Evershed effect in particular is due to overturning convection, mainly confined to gaps with strongly reduced magnetic field strength. The Evershed flow is the radial component of the overturning convective flow visible at the surface. It is directed outwards – away from the umbra – becau...
متن کاملTemporal evolution of the Evershed flow in sunspots II. Physical properties and nature of Evershed clouds
Context. Evershed clouds (ECs) represent the most conspicuous variation of the Evershed flow in sunspot penumbrae. Aims. We determine the physical properties of ECs from high spatial and temporal resolution spectropolarimetric measurements. Methods. The Stokes profiles of four visible and three infrared spectral lines are subject to inversions based on simple one-component models as well as mor...
متن کاملTemporal evolution of the Evershed flow in sunspots I. Observational characterization of Evershed clouds
Context. The magnetic and kinematic properties of the photospheric Evershed flow are relatively well known, but we are still far from a complete understanding of its nature. The evolution of the flow with time, which is mainly due to appearance of velocity packets called Evershed clouds (ECs), may provide information to further constrain its origin. Aims. We undertake a detailed analysis of the...
متن کاملSupersonic Continuation of the Evershed Flow outside a Sunspot as Observed with Hinode
We report on the discovery of mostly horizontal field channels just outside sunspot penumbrae (in the so-called ‘moat’ region) that are seen to sustain supersonic flows (line-of-sight component of 6 km s). The spectral signature of these supersonic flows corresponds to circular polarization profiles with an additional, satellite, third lobe of the same sign as the parent sunspot’ Stokes V blue ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 2018
ISSN: 1538-4357
DOI: 10.3847/1538-4357/aaa007