An exact analytic solution has been obtained for a uniformly expanding, neutral, infinitely conducting plasma cylinder in an external uniform and constant magnetic field. The electrodynamical aspects related to the emission and transformation of energy have been considered as well. The results obtained can be used in analysing the recent experimental and simulation data.
The coupling physics between multiple antennas separated axially along a plasma cylinder is investigated. Experiments are carried out on a recently built device: Physics ANd Thruster oriented HElicon Research (PANTHER), with an upgrade of second-stage antennas. Mutual induction currents are measured in detail. It is found that the existence of plasma column going through these antennas increase the coupling effects among them significantly. Theoretical analyses from the perspectives of transformer and magnetic permeability and moment confirm the reasonability of this phenomenon. This work is o…
The ultra low frequency modes associated to the activated dust specie in a bounded cylinder orientation plasma has been investigated here. Here flow of all plasma particles is assumed along the axial coordinates where gradients in velocity are set to be along radial direction. This analysis has been carried out for both Maxwellian and non-Maxwellian (Kappa and Carins) dusty plasma where coupling of electrostatic dust acoustic and drift modes drives global vortex formations. The coefficients of the vortex solution has been affected strongly by the presence of superthermal particles. Significanc…
Potential of a moving test charge in a dusty plasma in the presence of grain size distribution and grain charging dynamics
尘埃等离子体的线性介电响应受粒子尺寸分布的影响。在以前的结果[IEEE trans.Plasma Sci. 29，182（2001）]，表明对于一类尺寸分布，存在与单尺寸颗粒的洛伦兹分布的等价性。然后可以使用二阶近似法找到对缓慢移动的试探电荷的静电响应[Phys. Lett. A 305，79（2002）]。众所周知[Phys. Plasmas 10，3484（2003）]，尘埃等离子体中颗粒的动态充电增强了对试探电荷的屏蔽。在这一阶段，寻求颗粒尺寸分布和颗粒充电动力学对移动通过尘埃等离子体的试探电荷的组合效应似乎是自然的。在这里，我们考虑的晶粒尺寸分布和动态的晶粒充电的试探电荷在尘埃等离子体中缓慢移动的等离子体介电响应作为晶粒尺寸分布和晶粒充电动态的函数表示的影响。分析以及数值结果。值得注意的是，可以通过为不同的参数选择适当的值来检索以前的结果。这种研究对实验室和空间等离子体都有意义。
We consider the two-dimensional Vlasov-Poisson system to model a two-component plasma whose distribution function is constant with respect to the third space dimension. First, we show how this two-dimensional Vlasov-Poisson system can be derived from the full three-dimensional system. The existence of compactly supported steady states with vanishing electric potential in a three-dimensional setting has already been investigated by A. L. Skubachevskii [15]. We show that his approach can easily be adapted to the two-dimensional system. However, our main result is to prove the existence of compac…
The nature of fore-wake excitations created by a charged object moving in a magnetized plasma is investigated using particle-in-cell simulations. Our studies establish for the first time the existence of precursor magneto-sonic solitons traveling ahead of a moving charged object. The nature of these excitations and the conditions governing their existence are delineated. We also confirm earlier molecular dynamic and fluid simulation results related to electrostatic precursor solitons obtained in the absence of a magnetic field. The electromagnetic precursors could have interesting practical ap…
A charge bunch moving in a plasma can excite a variety of linear and nonlinear waves in the form of trailing wakes, fore-wake shocks and precursor solitons. These structures can further interact with the background plasma to create secondary effects that can serve as signatures of the passage of the charge bunch. Using particle-in-cell simulations we investigate in detail the dynamics of a plasma system that is being traversed by an energetic charged ion bunch. Using two different shapes of the charge source, namely, an idealized one dimensional line source and a two dimensional thin rectangul…
Negative energy wave phenomena may appear in shear flows in the presence of a wave decay mechanism and external energy supply. We study the appearance of negative energy surface waves in a plasma cylinder in the incompressible limit. The cylinder is surrounded by an axial magnetic field and by a plasma of different density. Considering flow inside and viscosity outside the flux tube, we derive dispersion relations, and obtain analytical solutions for the phase speed and growth rate (increment) of the waves. It is found that the critical speed shear for the occurrence of the dissipative instabi…
In a rotating magnetized plasma cylinder with shear, cross-field current can arise from inertial mechanisms and from the cross-field viscosity. Considering these mechanisms, it is possible to calculate the irreducible radial current draw in a cylindrical geometry as a function of the rotation frequency. The resulting expressions raise novel possibilities for tailoring the electric field profile by controlling the density and temperature profiles of a plasma.
Pinned solitons are a special class of nonlinear solutions created by a supersonically moving object in a fluid. They move with the same velocity as the moving object and thereby remain pinned to the object. A well known hydrodynamical phenomenon, they have been shown to exist in numerical simulation studies but to date have not been observed experimentally in a plasma. In this paper we report the first experimental excitation of pinned solitons in a dusty (complex) plasma flowing over a charged obstacle. The experiments are performed in a Π shaped Dusty Plasma Experimental (DPEx) device in wh…
We carry out expansions of non-symmetric toroidal ideal magnetohydrodynamic (MHD) equilibria with nested flux surfaces about a periodic cylinder, in which physical quantities are periodic of period $2π$ in the cylindrical angle $θ$ and $z$. The cross-section of a flux surface at a constant toroidal angle is assumed to be approximately circular, and data is given on the cylindrical flux surface $r=1$. Furthermore, we assume that the magnetic field lines are closed on the lowest order flux surface, and the magnetic shear is relatively small. We extend earlier work in a flat-torus by Weitzner [Ph…
Non conventional localized pulses, like offset bipolars have been reported in the Earths magnetosphere. The reports were sporadic and the theoretical interpretations were mainly event based which differ for slow or fast moving pulses. Here it was shown that the offset bipolar pulses are manifestations of an ideal, mathematically defined nonlinear coherent structure called a flat top soliton. Adopting Sagdeev pseudopotential technique, and assuming a simple plasma model, it was shown that a slow moving offset bipolar pulse in the auroral region can be interpreted as an ion acoustic flat top sol…
A peculiar ion behavior is found in a Si cluster, moving with a speed of ~0.22c (c: speed of light) in a solid Al plasma: the Si ion, moving behind the forward moving Si ion closely in a several angstrom distance in the cluster, feels the wake field generated by the forward Si. The interaction potential on the rear Si may balance the deceleration backward force by itself with the acceleration forward force by the forward Si in the longitudinal moving direction. The forward Si would be decelerated normally. However, the deceleration of the rear Si, moving behind closely, would be reduced signif…
