Related papers: The small-scale solar surface dynamo
We analyzed spectropolarimetric data from the Swedish 1-meter Solar Telescope to investigate physical properties of small-scale magnetic cancellations in the quiet Sun photosphere. Specifically, we looked at the full Stokes polarization…
Recent spectro-polarimetric observations have provided detailed measurements of magnetic field, velocity and intensity during events of magnetic field intensification in the solar photosphere. We consider the temporal evolution of the…
In the quiet Sun, magnetic fields are usually observed as small-scale magnetic elements, `salt and pepper', covering the entire solar surface. By using 3D radiative MHD numerical simulations we demonstrate that these fields are a result of…
We observed small scale magnetic flux emergence in a sunspot moat region by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed filtergram images observed in the wavelengths of Fe 6302 angstrom, G-band and Ca II H. In…
Standard statistical analysis of the magnetic properties of the quiet Sun rely on simple histograms of quantities inferred from maximum-likelihood estimations. Because of the inherent degeneracies, either intrinsic or induced by the noise,…
We report an extensive numerical study of the small-scale turbulent dynamo at large magnetic Prandtl numbers Pm. A Pm scan is given for the model case of low-Reynolds-number turbulence. We concentrate on three topics: magnetic-energy…
The theory of large scale dynamos is reviewed with particular emphasis on the magnetic helicity constraint in the presence of closed and open boundaries. In the presence of closed or periodic boundaries, helical dynamos respond to the…
Aims. Moreno-Insertis et al. (2018) recently discovered two types of flux emergence in their numerical simulations: magnetic loops and magnetic sheet emergence. Whereas magnetic loop emergence has been documented well in the last years, by…
In order to clarify a possible role of small-scale dynamo in formation of solar magnetic field, we suggest an observational test for small-scale dynamo action based on statistics of anti-Hale sunspot groups. As we have shown, according to…
In the past, spectropolarimetric data from Hinode/SP has been employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors have found predominantly horizontal magnetic fields, others favor an…
Disconnection of open magnetic flux by reconnection is required to balance the injection of open flux by CMEs and other eruptive events. Making use of recent advances in heliospheric background subtraction, we have imaged many abrupt…
The small-scale magnetic field is ubiquitous at the solar surface---even at high latitudes. From observations we know that this field is uncorrelated (or perhaps even weakly anticorrelated) with the global sunspot cycle. Our aim is to…
Small-scale dynamo action is often held responsible for the generation of quiet-Sun magnetic fields. We aim to determine the excitation conditions and saturation level of small-scale dynamos in non-rotating turbulent convection at low…
As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism…
We assess the global-scale dynamo action achieved in a simulation of a sun-like star rotating at three times the solar rate. The 3-D MHD Anelastic Spherical Harmonic code, using slope-limited diffusion, is employed to capture convection and…
The solar photosphere is filled by a magnetic field which is tangled on scales much smaller than the resolution capability of solar telescopes. This hidden magnetic field can be investigated via the Hanle effect. In 2007 we started a…
The unsigned mean magnetic field characterizes the magnetic energy settled in the region near the solar surface. It is one of the determinant ingredients that govern the turbulence in the photosphere, and the magnetic heating of upper…
Numerical MHD simulations play increasingly important role for understanding mechanisms of stellar magnetism. We present simulations of convection and dynamos in density-stratified rotating spherical fluid shells. We employ a new 3D…
Before using 3D MHD simulations of the solar photosphere in the determination of elemental abundances, one has to ensure that the correct amount of magnetic flux is present in the simulations. The presence of magnetic flux modifies the…
Turbulent magnetic fields fill most of the volume of the solar atmosphere. However, their spatial and temporal variations are still unknown. Since 2007, during the current solar minimum, we are periodically monitoring several wavelength…