Related papers: Spicule-like structures observed in 3D realistic M…
By means of self-consistent 3D MHD numerical simulations, we analyze magnetized solar-like stellar winds and their dependence on the plasma-beta parameter. We adopt in our simulations a heating parameter described by gamma, which is…
Stationary magnetohydrodynamic (MHD) outflows from a rotating, conducting Keplerian accretion disk threaded by B-field are investigated numerically by time-dependent, axisymmetric (2.5D) simulations using a Godunov-type code. A large class…
Recent Sunrise/IMaX observations have revealed the existence of supersonic magnetic flows. Our aim is to determine the origin of such flows by using realistic MHD simulations. We simulate cancellation and emergence of magnetic flux through…
Recent observations have shown that the photometric and dynamic properties of granulation and of small-scale magnetic features depend on the amount of magnetic flux of the region they are embedded in. We analyze results from numerical Hydro…
We have developed 3D, compressible, non-linear radiative MHD simulations to study the influence of the magnetic field of various strength and geometry on the turbulent convective cells and on the excitation mechanisms of the acoustic…
Context. We consider a localized pulse in the component of velocity, parallel to the ambient magnetic field lines, that is initially launched in the solar chromosphere. Aims. We aim to generalize the recent numerical model of spicule…
Context. For investigating spicules from the photosphere to coronal heights, the new Hinode/SOT long series of high resolution observations from Space taken in CaII H line emission offers an improved way to look at their remarkable…
We present the results of global 3-D MHD simulations of stratified and turbulent protoplanetary disc models. The aim of this work is to develop thin disc models capable of sustaining turbulence for long run times, which can be used for…
The solar photospheric magnetic field is highly structured owing to its interaction with the convective flows. Its local structure has a strong influence on the profiles of spectral lines not only by virtue of the Zeeman effect, but also…
The goal of this research is to investigate how magnetic field affects the dynamics of granular convection and excitation of solar oscillations by means of realistic numerical simulations. We have used a 3D, compressible, non-linear…
Giant planets embedded in protoplanetary disks (PPDs) can create annulus density gaps around their orbits in the type-II regime, potentially responsible for the ubiquity of annular substructures observed in PPDs. Despite of substantial…
Numerical methods to improve the treatment of magnetic fields in smoothed field magnetohydrodynamics (SPMHD) are developed and tested. Chapter 2 is a review of SPMHD. In Chapter 3, a mixed hyperbolic/parabolic scheme is developed which…
Through a direct comparison between numerical simulations in two and three dimensions, we investigate topological effects in reconnection. A simple estimate on increase in reconnection rate in three dimensions by a factor of $\sqrt{2}$,…
We present global 3D MHD simulations of geometrically thin but unstratified accretion disks in which a near Keplerian disk rotates between two bounding regions with initial rotation profiles that are stable to the MRI. The inner region…
The evolution of an initially stellar dipole type magnetosphere interacting with an accretion disk is investigated using numerical ideal MHD simulations. The simulations follow several 1000 Keplerian periods of the inner disk. The initial…
Spicules are among the most ubiquitous small-scale, jet-like features in the solar chromosphere and are widely believed to play a significant role in transporting mass and energy into the solar corona with their mechanisms not fully…
Spicules and other solar jets such as bright points and fibrils generally show a parabolic height-time relationship, which means that each spicule has a constant deceleration. However the deceleration is only constant for a particular…
This paper introduces a new approach for simulating magnetic properties of nanocomposites comprising magnetic particles embedded in a non-magnetic matrix, taking into account the 3D structure of the system in which particles' positions…
Magnetohydrodynamical (MHD) dynamos emerge in many different astrophysical situations where turbulence is present, but the interaction between large-scale (LSD) and small-scale dynamos (SSD) is not fully understood. We performed a…
We present full Stokes observations from SPINOR in the \ion{Ca}{2} infrared triplet and the \ion{He}{1} multiplet at 1083 nm from which some properties of spicules have been derived. There are important advantages in multi-line…