ﻻ يوجد ملخص باللغة العربية
New high-resolution observations reveal that small-scale magnetic flux concentrations have a delicate substructure on a spatial scale of 0.1. Its basic structure can be interpreted in terms of a magnetic flux sheet or tube that vertically extends through the ambient weak-field or field-free atmosphere with which it is in mechanical equilibrium. A more refined interpretation comes from new three-dimensional magnetohydrodynamic simulations that are capable of reproducing the corrugated shape of magnetic flux concentrations and their signature in the visible continuum. Furthermore it is shown that the characteristic asymmetric shape of the contrast profile of facular granules is an effect of radiative transfer across the rarefied atmosphere of the magnetic flux concentration. I also discuss three-dimensional radiation magnetohydrodynamic simulations of the integral layers from the top of the convection zone to the mid-chromosphere. They show a highly dynamic chromospheric magnetic field, marked by rapidly moving filaments of stronger than average magnetic field that form in the compression zone downstream and along propagating shock fronts. The simulations confirm the picture of flux concentrations that strongly expand through the photosphere into a more homogeneous, space filling chromospheric field. Future directions in the simulation of small-scale magnetic fields are indicated by a few examples of very recent work.
Magnetic fields in galaxies and galaxy clusters are amplified from a very weak seed value to the observed $mu{rm G}$ strengths by the turbulent dynamo. The seed magnetic field can be of primordial or astrophysical origin. The strength and structure o
We consider the conditions under which a rotating magnetic object can produce a magnetically powered outflow in an initially unmagnetized medium stratified under gravity. 3D MHD simulations are presented in which the footpoints of localized, arcade-s
A weak fluctuating magnetic field embedded into a turbulent conducting medium grows exponentially while its characteristic scale decays. In the ISM and protogalactic plasmas, the magnetic Pr is very large, so a broad spectrum of growing magnetic fluc
The Hard X-ray Modulation Telescope HXMT or also dubbed as Insight HXMT is China s first astronomical satellite . It was launched on 15 th June 2017 in JiuQuan, China and is currently in service smoothly. It was designed to perform point ing , scan n
While the longitudinal field that dominates photospheric network regions has been studied extensively, small scale transverse fields have recently been found to be ubiquitous in the quiet internetwork photosphere. Few observations have captured how t