共查询到19条相似文献,搜索用时 62 毫秒
1.
通过使用推广的 Poincar-Lighthill-Kuo 摄动方法,研究了二维热离子等离子体中两个沿不同方向传播的离子声孤波的相互作用,得到了两个分别描述沿ξ和η方向传播的孤波的KdV方程以及两个孤波以任意夹角碰撞后的相移和轨道.同时还研究了离子温度比σ、热容比γ和碰撞夹角α对孤波相移的影响.研究表明,这些参量可以明显地改变孤波的相移,且在该系统中存在压缩型孤波.
关键词:
热离子等离子体
离子声孤波
Poincar-Lighthill-Kuo方法
相移 相似文献
2.
研究了由尘埃颗粒、电子和非热离子所组成的非磁化热尘埃等离子体中(2+1)维非线性尘埃声孤波的传播特征.首先,利用约化摄动法推导得到了用来描述(2+1)维非线性尘埃声孤波的Kadomtsev-Petviashvili(KP)方程,并采用行波解法进行了定性分析,从而获得了该系统的相图及Sagdeev势方程;然后,利用数学软件的数值模拟分析方法讨论了等温和绝热两种状态下,热尘埃等离子体系统中不同参数对KP方程的非线性系数、色散系数、系统相图、Sagdeev势函数及孤立波解的影响.最终,研究结果表明:等温和绝热状态下,尘埃颗粒的质量、电子和非热离子的温度、数密度及分布状态等多种系统参数对非线性尘埃声孤波的振幅、宽度及波形等传播特征均存在重要影响. 相似文献
3.
4.
5.
6.
7.
从理论上研究了非热离子、外部磁场、碰撞对非均匀热尘埃等离子体中三维非线性尘埃声孤波的影响。运用约化摄动法得到描述三维非线性尘埃声孤波的非标准的变系数Korteweg-de Vries(KdV)方程。然后把非标准KdV方程变为标准的变系数KdV方程,并且得到了标准的变系数KdV方程的近似解析解。由此解析解可以看出,非热离子的数目、碰撞、非均匀性、波的斜向传播、尘埃颗粒和非热离子的温度对三维非线性尘埃声孤波的振幅和宽度有很大的影响。外部磁场对三维非线性尘埃声孤波的宽度有影响,而对其振幅没有影响。此外,波的相速度与非热离子、波的斜向传播、尘埃颗粒的温度和非均匀性有关。 相似文献
8.
9.
10.
详细地讨论了托卡马克等离子体对离子回旋波非全吸收,离子回旋共振加热天线为三维模型的条件下,离子回旋波与等离子体的耦合问题。与全吸收等离子体模型所计算得到的结果相比,本文得到的波的驻波场的解及耦合阻抗谐振特性的理论计算结果与中小型托卡马克实验所观察到的现象更为接近。 相似文献
11.
Hamid Reza Pakzad 《Indian Journal of Physics》2009,83(11):1605-1613
The Korteweg-de Vries equation for a weakly relativistic ion acoustic wave propagating in oollisionless plasma containing
nonthermal electron, positron and warm ion is derived. The effects of the ion temperature, nonthermal parameter and relativistic
effect on the amplitude, width and energy of soliton are studied. 相似文献
12.
Due to the presence of a relatively cold electron component in a plasma, the ion acoustic solitary wave of a given width has a larger amplitude. When the temperature difference between the two electron components is sufficiently large, the strength of dispersion is reduced to an extent that a solitary solution is no longer possible. 相似文献
13.
Modulational instability of a weakly relativistic ion acoustic wave in a warm plasma with nonthermal electrons 下载免费PDF全文
An investigation has been made of modulational instability of a nonlinear ion acoustic wave in a weakly relativistic warm unmagnetized nonthermal plasma whose constituents are an inertial ion fluid and nonthermally distributed electrons. Up to the second order of the perturbation theory, a nonlinear Schr?dinger type (NST) equation for the complex amplitude of the perturbed ion density is obtained. The coefficients of this equation show that the relativistic effect, the finite ion temperature and the nonthermal electrons modify the condition of the modulational stability. The association between the small-wavenumber limit of the NST equation and the oscillatory solution of the Korteweg-de Varies equation, obtained by a reductive perturbation theory, is satisfied. 相似文献
14.
Alireza Abdikian 《等离子体物理论文集》2019,59(1):20-30
The nonlinear dust‐ion‐acoustic (DIA) solitary structures have been studied in a dusty plasma, including the Cairns‐Gurevich distribution for electrons, both negative and positive ions, and immobile opposite polarity dust grains. The external magnetic field directed along the z‐axis is considered. By using the standard reductive perturbation technique and the hydrodynamics model for the ion fluid, the modified Zakharov–Kuznetsov equation was derived for small but finite amplitude waves and was provided the solitary wave solution for the parameters relevant. Using the appropriate independent variable, we could find the modified Korteweg–de Vries equation. By plotting some figures, we have discussed and emphasized how the different plasma values, such as the trapping parameter, the positive (or negative) dust number density, the non‐thermal electron parameter, and the ion cyclotron frequency, can influence the solitary wave structures. In addition, using the bifurcation theory of planar dynamical systems, we have extracted the centre and saddle points and illustrated the phase portrait of such a system for some particular plasma parameters. Finally, we have graphically investigated the behaviour of the solitary energy wave by changing the plasma values as well as by calculating the instability criterion; we have also discussed the growth rate of the solitary waves. The results could be useful for studying the physical mechanism of nonlinear propagation of DIA solitary waves in laboratory and space plasmas where non‐thermal electrons, pair‐ions, and dust particles can exist. 相似文献
15.
《等离子体物理论文集》2017,57(9):373-376
This paper considers ion‐acoustic waves in a plasma in which the ions move unidirectionally. The dispersion equation is considered and analysed as a two‐dimensional problem. It is shown that the ion‐acoustic waves can be in the form of backward waves (BWs ). The area boundaries in the plane {k x , k y } where the BW exists are found. 相似文献
16.
Abu Shahed Mohammad Moinuddin Mohammad Shah Alam Mamunur Rashid Talukder 《等离子体物理论文集》2020,60(7):e201900124
The effects of head-on collision on dust acoustic (DA) solitary and shock waves in dusty plasma are investigated considering positively charged inertial dust, Boltzmann distributed negatively charged heavy ions, positively charged light ions, and superthermal electrons in the plasma system. The nonlinear Korteweg-de-Vries (KdV) Burger equations are derived taking the extended Poincaré-Lighthill-Kuo method into account to study the characteristic properties of nonlinearity and production of solitary shock due to collisions. The study reveals that the amplitudes and widths of the DA shock waves are decreasing with increasing viscosity, electron to dust density ratio, and dust to ion temperature ratio, while they are increasing due to the presence of superthermal electrons. The nonlinearity of DA waves are enhanced with increasing density ratio of electron to dust and temperature ratio of dust to ion and electron, respectively, but it is reducing with superthermal electrons. The phase shifts of DA solitary waves are found to decrease with rising superthermality of electrons and increase with the density ratio of electron to dust. 相似文献
17.
A theory for dressed quantum ion acoustic waves (QIAWs), which includes higher-order corrections when QIAWs are investigated by the reductive perturbation method, is presented for unmagnetized plasmas containing positive and negative ions and weakly relativistic electron beams. The properties of the QIAWs are investigated using a quantum hydrodynamic model, from which a Korteweg–de Vries equation is derived using the reductive perturbation method. An equation including higher-order dispersion and nonlinearity corrections is also derived, and the physical parameter space is discussed for the importance of these corrections. 相似文献
18.
The separate spin evolution quantum hydrodynamics(SSE-QHD) model is used to investigate the energy behavior for ion acoustic waves in degenerate quantum plasma. Numerical results show that the energy flow speed decreases with spin polarization parameter. It is also shown that it decreases with the increasing rate up to a certain range of wave number and then it goes to zero asymtotically. It is observed that Bohm potential suppresses the energy flow speed. It is also noticed that the energy flow speed deviates from the group velocity even in the absence of Bohm potential effect. However, the contribution of of Bohm poential effect in spin polarized plasma reduces the extent of deviation. 相似文献
19.
Propagation and interaction of ion-acoustic solitary waves in a quantum electron-positron-ion plasma 下载免费PDF全文
This paper discusses the existence of ion-acoustic solitary waves and their interaction in a dense quantum electron-positron-ion plasma by using the quantum hydrodynamic equations.The extended Poincar’e-Lighthill-Kuo perturbation method is used to derive the Korteweg-de Vries equations for quantum ion-acoustic solitary waves in this plasma.The effects of the ratio of positrons to ions unperturbation number density p and the quantum diffraction parameter H e (H p) on the newly formed wave during interaction,and the phase shift of the colliding solitary waves are studied.It is found that the interaction between two solitary waves fits linear superposition principle and these plasma parameters have significantly influence on the newly formed wave and phase shift of the colliding solitary waves.The investigations should be useful for understanding the propagation and interaction of ion-acoustic solitary waves in dense astrophysical plasmas (such as white dwarfs) as well as in intense laser-solid matter interaction experiments. 相似文献