Three-dimensional model for generation of the mean solar magnetic field

1985 ◽  
Vol 306 (4) ◽  
pp. 177-186 ◽  
Author(s):  
T. S. Ivanova ◽  
A. A. Ruzmaikin
Keyword(s):  
Magnetic Field ◽  
Solar Magnetic Field ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
The Mean

scholarly journals Coronal ejections from convective spherical shell dynamos

2011 ◽  
Vol 7 (S286) ◽  
pp. 154-158 ◽  
Author(s):  
J. Warnecke ◽  
P. J. Käpylä ◽  
M. J. Mantere ◽  
A. Brandenburg
Keyword(s):  
Magnetic Field ◽  
Spherical Shell ◽  
Large Scale ◽  
Convection Zone ◽  
Three Dimensional ◽  
Simplified Model ◽  
Spherical Coordinates ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Large Scale Magnetic Field

AbstractWe present a three-dimensional model of rotating convection combined with a simplified model of a corona in spherical coordinates. The motions in the convection zone generate a large-scale magnetic field which is sporadically ejected into the outer layers above. Our model corona is approximately isothermal, but it includes density stratification due to gravity.

‘Mean Contrast’ Texture Feature Model of Nature Environmental Protection Fabric

2010 ◽  
Vol 113-116 ◽  
pp. 943-946
Author(s):  
Zhe Liu
Keyword(s):  
Three Dimensional ◽  
Texture Feature ◽  
Feature Model ◽  
Quality Inspection ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Numerical Convergence ◽  
Texture Characteristics ◽  
The Mean ◽  
Contrast Feature

Aiming at lack of mature texture feature model of natural green fabric image, this paper presents a new “Mean Contrast” texture feature model, which can express better on the type of collecting and narrow-long and some irregular defects. First, three-dimensional model of texture characteristics is established, various natural green fabrics are tested in experiments using the contrast feature, and then “Mean Contrast” feature is proposed, so that characteristic value of fabric texture can be converged. Finally, experimental results show that the “mean contrast” feature is so simple and effective that better show a variety of fabric texture variation, and has the numerical convergence. So it provides a contrasting texture feature model for continue related to fabric quality inspection.

Electrostatic plasma turbulence Part 1. Turbulent plasma diffusion across a magnetic field

1976 ◽  
Vol 15 (2) ◽  
pp. 279-292 ◽  
Author(s):  
H. C. Barr ◽  
T. J. M. Boyd
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Particle Energy ◽  
Dimensional Model ◽  
Fluctuation Spectrum ◽  
Three Dimensional Model ◽  
Continuous Transition ◽  
Strong Magnetic Fields ◽  
Plasma Diffusion ◽  
The Magnetic Field

The turbulent diffusion of plasma across a magnetic field is studied theoretically using a three-dimensional model which includes the full dynamics of the diffusing particles and which is valid for arbitrary magnetic field strengths. The theory is confined to perpendicular turbulence, i.e. where the build-up of the fluctuations lies primarily in the plane perpendicular to the magnetic field (although it is more generally applicable). A single expression for the diffusion is derived in terms of the fluctuation spectrum, particle energy, the dispersion characteristics of the excited modes and the magnetic field. Earlier results for equilibrium plasmas are confirmed. We demonstrate the continuous transition from anomalous (1/B) diffusion in regimes of low fluctuation levels (or strong magnetic fields) to classical (1/B2) diffusion in regimes where the fluctuation level destroys the coherence sustained by the magnetic field. In this latter regime, the particles behave as if unmagnetized except for a turbulent drift which appears in the presence of anisotropic spectra.

Developing a Hybrid Three-Dimensional Model of a Plasma Cloud Undergoing Collisionless Expansion into a Rarefied Ionised Magnetized Medium

2021 ◽  
pp. 112-132
Author(s):  
A.S. Dikalyuk
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Numerical Scheme ◽  
Three Dimensional ◽  
System Of Equations ◽  
Plasma Cloud ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Induction Equation ◽  
Simulation Results

The paper presents the results of developing a hybrid three-dimensional model of collisionless interaction in plasma flows. This model considers ions in kinetical terms (simulated as a set of individual particles) and describes electrons in terms of continuum mechanics (simulated as a fluid). We present the system of equations behind the mathematical model and the physical conditions limiting its applicability. The system includes equations describing ion motion in electromagnetic fields, the quasineutrality equation, equations for calculating the total current density, non-radiative Maxwell's equations, and the generalised Ohm's law. We outline a numerical method for solving our hybrid model equations and describe an algorithm for solving the system of equations over time. We focus on the numerical method for solving the induction equation, which takes possible discontinuous solutions into account and preserves the divergence-free condition for the magnetic field. The paper discusses the issues of increasing the spatial approximation accuracy for the numerical scheme used to solve the induction equation. We present numerical simulation results for collisionless expansion of a plasma cloud into a rarefied ionised gas in the presence of an external magnetic field. These results were obtained using our computer code that implements the hybrid model described. The paper demonstrates some numerical properties of the digital simulation developed, specifically, how the order of accuracy for the numerical scheme approximation designed to solve the induction equation affects numerical simulation results

Sign in / Sign up

Export Citation Format

Share Document