scholarly journals Numerical solution of the Vlasov-Maxwell system of equations for cylindrical plasmas

2019 ◽  
Vol 1247 ◽  
pp. 012005
Author(s):  
Jaime H Hoyos ◽  
Sebastian Ramirez ◽  
Jose A Valencia
Keyword(s):  
Numerical Solution ◽  
System Of Equations ◽  
Maxwell System

Motion of a Large Dusty Buoyant Thermal With a Vortex Ring

1978 ◽  
Vol 45 (4) ◽  
pp. 711-716 ◽  
Author(s):  
Stephen S.-H. Chang
Keyword(s):  
Numerical Solution ◽  
Vortex Ring ◽  
Excellent Agreement ◽  
Spherical Particles ◽  
System Of Equations ◽  
Inhomogeneous Atmosphere

This paper presents a method for computing the motion and decay of a large dusty, buoyant thermal (cloud) carried by a vortex ring generated from a strong near ground explosion and ascending in an inhomogeneous atmosphere. A system of equations is derived describing the motion of the vortex ring, the thermal, and the pollutants which consist of numerous solid spherical particles. The interior properties and the trajectories of the thermal and the pollutants are obtained. The numerical solution for the thermal trajectory is in excellent agreement with experiment.

scholarly journals Numerical solution for consistent initial conditions of constrained mechanical systems

2003 ◽  
Vol 25 (3) ◽  
pp. 170-185
Author(s):  
Dinh Van Phong
Keyword(s):  
Numerical Solution ◽  
Initial Conditions ◽  
Equations Of Motion ◽  
Mechanical Systems ◽  
Differential Algebraic Equations ◽  
System Of Equations ◽  
Algebraic Equations ◽  
Flexible Approach ◽  
Constrained Mechanical Systems ◽  
Consistent Initial Values

The article deals with the problem of consistent initial values of the system of equations of motion which has the form of the system of differential-algebraic equations. Direct treating the equations of mechanical systems with particular properties enables to study the system of DAE in a more flexible approach. Algorithms and examples are shown in order to illustrate the considered technique.

scholarly journals A SLOWLY ROTATING CHARGED BLACK HOLE IN FIVE DIMENSIONS

2006 ◽  
Vol 21 (09) ◽  
pp. 751-757 ◽  
Author(s):  
A. N. ALIEV
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
System Of Equations ◽  
Maxwell System ◽  
Five Dimensions ◽  
Four Dimensions ◽  
Higher Dimensional ◽  
Long Time ◽  
Electrically Charged ◽  
Black Hole Solutions

Black hole solutions in higher dimensional Einstein and Einstein–Maxwell gravity have been discussed by Tangherlini as well as Myers and Perry a long time ago. These solutions are the generalizations of the familiar Schwarzschild, Reissner–Nordström and Kerr solutions of four-dimensional general relativity. However, higher dimensional generalization of the Kerr–Newman solution in four dimensions has not been found yet. As a first step in this direction we shall report on a new solution of the Einstein–Maxwell system of equations that describes an electrically charged and slowly rotating black hole in five dimensions.

scholarly journals Решетки населенностей, создаваемые парой униполярных аттосекундных импульсов в трехуровневой атомарной среде

2020 ◽  
Vol 128 (11) ◽  
pp. 1732
Author(s):  
Р.М. Архипов
Keyword(s):  
Approximate Solution ◽  
Schrödinger Equation ◽  
Density Matrix ◽  
Numerical Solution ◽  
Schrodinger Equation ◽  
Resonant Medium ◽  
System Of Equations ◽  
Atomic Vapors ◽  
Attosecond Pulses ◽  
Level Medium

The possibility of population gratings creation in a three-level resonant medium using a pair of unipolar attosecond pulses that do not overlap in the medium is studied theoretically. It is shown that the results of the approximate solution of the Schrödinger equation agree with the results of the numerical solution of the system of equations for the density matrix of a three-level medium, the parameters of which are close to the parameters of atomic vapors of rubidium.

scholarly journals An Optimal Algorithm for the Solution of the Helmholtz Equation

2020 ◽  
pp. 121-133
Author(s):  
Richard O. Akinola ◽  
Blessing Okwudo Ogbeh ◽  
Isaac Chukle
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Helmholtz Equation ◽  
Numerical Solution ◽  
Optimal Algorithm ◽  
Weather Prediction ◽  
System Of Equations ◽  
Partial Differential ◽  
Linear System Of Equations ◽  
Seidel Method

Aims/Objectives: The Helmholtz equation is a partial differential equation which is used in numerical weather prediction. Angwenyi et. al., used a five point finite difference stencil in discretizing the partial differential equation and solved the resulting square system of equations using eight iterative methods and concluded that the BICGSTAB was the most computationally efficient using just one example. However, based on a comparison of the norm of the residual and CPU time of four methods presented in this work on the same example in their paper and others; we not only discovered that the Gauss Seidel method out performed the BICGSTAB contradicting the claim of the authors but also the Thomas Block Tridiagonal Algorithm (TBTA)in the absence of round off errors.Methodology: We compared the performance of the Gauss Seidel Method, BICGSTAB, Matlab backslash, and the Thomas Block Tridiagonal Algorithm (TBTA) for the numerical solution of the Helmholtz equation with different step sizes. Results: We discovered that in the absence of round off errors, not only did the Gauss Seidel method but also the Thomas Block Tridiagonal Algorithm (TBTA) out performed the BICGSTAB contradicting the claim of Angwenyi et. al.Conclusion: We do not recommend the BICGSTAB for the solution of the linear system of equations arising from the discretization of the Helmholtz equation as claimed by Angwenyi et al. Rather, the Thomas Block Tridiagonal Algorithm should be used and if one is thinking of an iterative method for the numerical solution of the Helmholtz equation, the Gauss-Seidel method should be the method of choice rather than the BICGSTAB.

scholarly journals ANALYSIS OF THE CONSERVATIVE SMOOTHING EFFECT ON THE ACCURACY OF DYNAMIC ELASTIC-PLASTIC SPHERICAL SHELLS BUCKLING NUMERICAL SIMULATION

2019 ◽  
Vol 81 (4) ◽  
pp. 474-487
Author(s):  
A.V. Demareva
Keyword(s):  
Experimental Data ◽  
Spherical Shell ◽  
Numerical Solution ◽  
Initial Conditions ◽  
Local Coordinate System ◽  
Isotropic Hardening ◽  
System Of Equations ◽  
State Equations ◽  
Defining System ◽  
Smoothing Procedure

Large changes of a lead spherical shell enclosed in an aluminum spacesuit under the action of an overload pulse are considered. The defining system of equations is formulated in Lagrange variables in a two-dimensional (axisymmetric) formulation. Strain and stress rates are determined in the local coordinate system. Kinematic relations are recorded in the metric of the current state. The relations of the flow theory with isotropic hardening are used as state equations. The contact interaction of the shell and the spacesuit is modeled by non-penetration conditions taking into account friction. The numerical solution of the problem under given boundary and initial conditions is based on the finite element method moment scheme and the explicit time integration “cross” type scheme. 4-node isoparametric finite elements with bilinear form functions are used to discretize the defining system of equations for spatial variables. To suppress the numerical solution high-frequency oscillations, the procedure of nodal displacements rates conservative smoothing is used. As shown by the results of numerical research spherical shell in the process of intensive dynamic loading undergoes large deformation and rotation angles as a rigid whole. The calculation results reliability is confirmed by a good correspondence to the experimental data. The influence of conservative smoothing procedure and moment components of deformations and stresses on the solution accuracy is analyzed. It is shown that without conservative smoothing procedure using, the shape of the spherical shell buckling obtained in the calculation does not correspond to the experimental data. Neglect of the moment components of strains and stresses leads to the development of instability of the “hourglass” type.

scholarly journals ANALYTICAL MODELS FOR QUARK STARS

2007 ◽  
Vol 16 (11) ◽  
pp. 1803-1811 ◽  
Author(s):  
K. KOMATHIRAJ ◽  
S. D. MAHARAJ
Keyword(s):  
Electromagnetic Field ◽  
Equation Of State ◽  
Exact Solutions ◽  
Quark Matter ◽  
Matter Content ◽  
Analytical Models ◽  
System Of Equations ◽  
Maxwell System ◽  
Elementary Functions ◽  
Quark Stars

We find two new classes of exact solutions to the Einstein–Maxwell system of equations. The matter content satisfies a linear equation of state consistent with quark matter; a particular form of one of the gravitational potentials is specified to generate solutions. The exact solutions can be written in terms of elementary functions, and these can be related to quark matter in the presence of an electromagnetic field. The first class of solutions generalizes the Mak–Harko model. The second class of solutions does not admit any singularities in the matter and gravitational potentials at the center.

A Numerical Scheme for the Integration of the Vlasov–Maxwell System of Equations

2002 ◽  
Vol 179 (2) ◽  
pp. 495-538 ◽  
Author(s):  
A. Mangeney ◽  
F. Califano ◽  
C. Cavazzoni ◽  
P. Travnicek
Keyword(s):  
Numerical Scheme ◽  
System Of Equations ◽  
Maxwell System
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