scholarly journals Numerical simulation of a slow extraordinary wave in magnetoactive plasma

Author(s):  
Е.В. Чижонков ◽  
А.А. Фролов

Численно и аналитически исследовано влияние внешнего магнитного поля на плоские нерелятивистские нелинейные плазменные колебания. Для инициализации медленной необыкновенной волны в магнитоактивной плазме предложен способ построения недостающих начальных условий на основе решения линейной задачи методом Фурье. С целью численного моделирования нелинейной волны построена схема метода конечных разностей второго порядка точности типа МакКормака на основе эйлеровых переменных. Показано, что при учете внешнего магнитного поля ленгмюровские колебания трансформируются в медленную необыкновенную волну, энергия которой вибрирует при перемещении от начала координат. При этом скорость волны увеличивается с ростом внешнего постоянного поля, что способствует выносу энергии из первоначальной области локализации колебаний. The effect of an external magnetic field on plane non-relativistic nonlinear plasma oscillations is studied numerically and analytically. A method for the initialization a slow extraordinary wave in a magnetoactive plasma is proposed for constructing the missing initial conditions based on solving a linear problem using the Fourier method. For the purpose of numerical simulation of a nonlinear wave, a scheme of the second-order accuracy finite difference method of the MacCormack type based on Euler variables is constructed. It is shown that, when the external magnetic field is taken into account, the Langmuir oscillations are transformed into a slow extraordinary wave whose energy vibrates when moving from the origin. In this case, the wave velocity increases with the growth of the external constant field, which contributes to the removal of energy from the initial region of localization of oscillations.

2020 ◽  
Vol 34 (07) ◽  
pp. 2050044
Author(s):  
Mehdi Abedi-Varaki

In this paper, self-focusing of intense laser pulse propagating along the obliquely external magnetic field on the collisional magnetoactive plasma by using the perturbation theory have been studied. The wave equation describing the interaction of intense laser pulse with collisional magnetoactive plasma is derived. In addition, employing source-dependent expansion (SDE) method, the analysis of the laser spot-size is discussed. It is shown that with increasing of the angle in obliquely external magnetic field, the spot-size of laser pulse decreases and as a result laser pulse becomes more focused. Furthermore, it is concluded that the self-focusing quality of the laser pulse has been enhanced due to the presence of obliquely external magnetic field in the collisional magnetoactive plasma. Besides, it is seen that with increasing of [Formula: see text], the laser spot-size reduces and subsequently the self-focusing of the laser pulse in plasma enhances. Moreover, it is found that changing the collision effect in the magnetoactive plasma leads to increases of self-focusing properties.


2014 ◽  
Vol 89 (24) ◽  
Author(s):  
D. L. Boyda ◽  
V. V. Braguta ◽  
S. N. Valgushev ◽  
M. I. Polikarpov ◽  
M. V. Ulybyshev

2011 ◽  
Vol 239-242 ◽  
pp. 3096-3099
Author(s):  
Ming Hua Bai ◽  
Hong Liang Zhou

Magnetic fluid as a functional material can produce volume force under external magnetic field, for the purpose of controlling the magnetic fluid flow state in the non-magnetic sealing groove with external magnetic field, the volume force is written as a function form of AZ to do with the numerical simulation of magnetic fluid flow in the sealing groove. The result shows that the magnetic fluid which distributes at the right-angle edges of the two permanent magnets nearby the separator presents unsteady swirl flow due to the volume force, while the rest magnetic fluid is in the quiescent state. It means that the magnetic fluid seal method can effectively solve the air leakage of band sintering machine and circular cooling machine.


2009 ◽  
Vol 107 (5) ◽  
pp. 1844-1847 ◽  
Author(s):  
Mojca Vilfan ◽  
Anton Potočnik ◽  
Blaž Kavčič ◽  
Natan Osterman ◽  
Igor Poberaj ◽  
...  

Due to their small dimensions, microfluidic devices operate in the low Reynolds number regime. In this case, the hydrodynamics is governed by the viscosity rather than inertia and special elements have to be introduced into the system for mixing and pumping of fluids. Here we report on the realization of an effective pumping device that mimics a ciliated surface and imitates its motion to generate fluid flow. The artificial biomimetic cilia are constructed as long chains of spherical superparamagnetic particles, which self-assemble in an external magnetic field. Magnetic field is also used to actuate the cilia in a simple nonreciprocal manner, resulting in a fluid flow. We prove the concept by measuring the velocity of a cilia-pumped fluid as a function of height above the ciliated surface and investigate the influence of the beating asymmetry on the pumping performance. A numerical simulation was carried out that successfully reproduced the experimentally obtained data.


2020 ◽  
Vol 20 (1) ◽  
pp. 63-73
Author(s):  
Vitalii Kapitan ◽  
◽  
Egor Vasiliev ◽  
Yuriy Shevchenko ◽  
Alexander Perzhu ◽  
...  

We present results of numerical simulation of thermodynamics for array of Classical Heisenberg spins placed on 2D square lattice. By using Metropolis and Wang--Landau methods we show the temperature behaviour of system with competing Heisenberg and Dzyaloshinskii--Moriya interaction (DMI) in contrast with classical Heisenberg system. We show the process of nucleating of skyrmion depending on the value of external magnetic field.


1972 ◽  
Vol 7 (3) ◽  
pp. 445-459 ◽  
Author(s):  
J. R. Kan

A class of equilibrium configurations of Vlasov plasmas carrying a current component along an external magnetic field is presented. The present slab model contains the diamagnetic current jy, and the field-aligned current jz for arbitrary βc (= particle pressure/magnetic pressure of the applied constant field). For fixed βc and field-aligned current, our model admits a family of equilibrium solutions in which the diamagnetic currents range from zero to a maximum value. The amount of diamagnetic current flowing in a machine depends on the width of the machine, the field-aligned current and other plasma parameters. The Helmholtz free energy of the system is calculated under the constraints that the total number of particles and the field-aligned current are conserved. The least unstable equilibrium configuration in a machine is obtained by minimizing the free energy under the stated constraints among all equilibria whose plasma widths do not exceed the width of the machine.


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