Related papers: Optimizing helical disc dynamo
Disc-winds originating from the inner parts of accretion discs are considered as the basic component of magnetically collimated outflows. The only available analytical MHD solutions to describe disc-driven jets are those characterized by…
We consider the generation of magnetic activity --- dynamo waves --- in the astrophysical limit of very large magnetic Reynolds number. We consider kinematic dynamo action for a system consisting of helical flow and large-scale shear. We…
Understanding the in situ amplification of large scale magnetic fields in turbulent astrophysical rotators has been a core subject of dynamo theory. When turbulent velocities are helical, large scale dynamos that substantially amplify…
Till now the magnetohydrodynamic (MHD) simulation of the reversed field pinch (RFP) has been performed by assuming axis-symmetric radial time independent dissipation profiles. In helical states this assumption is not correct since these…
We present MHD simulations exploring the launching, acceleration and collimation of jets and disk winds. The evolution of the disk structure is consistently taken into account. Extending our earlier studies, we now consider the…
Since its commissioning in 1977, the U-120M cyclotron has been equipped with one pair of harmonic coils dedicated to establishing optimal beam quality at low accelerating radii. In 2022, the cyclotron was upgraded and a second pair of…
Direct numerical simulations are performed for the steady flow normal to a circular disk at the Reynolds number of 1000. Numerical simulations are conducted with different levels of simplification procedure by reducing the azimuthal…
We use a simple model of Bullard-type disc dynamo, in which the disc rotation rate is subject to harmonic oscillations, to analyze the generation of magnetic field by the parametric resonance mechanism. The problem is governed by a damped…
The exact relativistic treatment of a rotating disk surrounded by a magnetized material halo is presented. The features of the halo and disk are described by the distributional energy-momentum tensor of a general fluid in canonical form.…
We use a 3D radiative non-ideal magnetohydrodynamic (MHD) simulation to investigate the formation and evolution of a young protostellar disc from a magnetized pre-stellar core. The simulation covers the first ${\sim}10~{\rm kyr}$ after…
The formation of rotationally supported protostellar disks is suppressed in ideal MHD in non-turbulent cores with aligned magnetic field and rotation axis. A promising way to resolve this so-called "magnetic braking catastrophe" is through…
Analytical solution of ${\alpha}$-dynamo equation representing strongly torsioned helical dynamo is obtained in the thin twisted Riemannian flux tubes approximation. The $\alpha$ factor possesses a fundamental contribution from torsion…
In most current debris disc models, the dynamical and the collisional evolutions are studied separately, with N-body and statistical codes, respectively, because of stringent computational constraints. We present here LIDT-DD, the first…
The reduction of magnetic forces on electromagnetic coils is an important consideration in the design of high-field devices such as the stellarator or tokamak. Unfortunately, these forces may be too time-consuming to evaluate by…
Cycloidal propellers are known for their omnidirectional vectored thrust, enabling smooth transitions between hovering and forward flight, making them ideal for unmanned aerial vehicles (UAVs) and electric vertical take-off and landing…
The poorly-ionized interior of the protoplanetary disk is the location where dust coagulation processes may be most efficient. However even here, planetesimal formation may be limited by the loss of solid material through radial drift, and…
In the standard picture of disc galaxy formation, baryons and dark matter receive the same tidal torques, and therefore approximately the same initial specific angular momentum. However, observations indicate that disc galaxies typically…
The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude fast amplification processes…
Helical solenoids have been proposed as an option for a Helical Cooling Channel for muons in a proposed Muon Collider. Helical solenoids can provide the required three main field components: solenoidal, helical dipole, and a helical…
By postulating that the majority of the mass and angular momentum of a disc galaxy is confined to the disc with a lognormal surface density distribution, and that galactic discs are substantially, if not fully, self-gravitating, it may be…