共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
研究了赤道电离层等离子体交换不稳定性和大气重力波的耦合性质。如果没有外部扰动的影响,非线性效应使交换不稳定性饱和在一个很小的幅度上。在适当的条件下,重力波能触发交换不稳定性。如果重力波的幅度足够大,所触发的交换不稳定性的扰动幅度能达到50%甚至更大,产生等离子体泡,本文的理论揭示了电离层大尺度扩展F的产生机制,可以解释许多重要的电离层观测现象。
关键词: 相似文献
3.
简单磁镜中热电子等离子体的基本特性 总被引:1,自引:1,他引:0
本文叙述了简单磁镜中,热电子等离子体的实验结果。微波在基频共振层击穿气体产生等离子体,二次偕振加热产生热电子环。等离子体激发了低频交换模和漂移波,热电子环对等离子体的扰动有稳定作用。 相似文献
4.
本文用磁流体理论导出了热电子等离子体中,等离子体密度梯度驱动的低频漂移波的色散关系,分析了热电子的稳定作用。热电子成分稳定等离子体低频扰动的物理机制是charge uncovering效应,它只依赖于热电子同等离子体的密度比α,而不依赖于热电子的β值。热电子能降低等离子体交换模和漂移波的增长率,减少漂移波引起的等离子体反常输运损失。稳定等离子体交换模要求α≈2%,稳定等离子体漂移波要求α≈40%。理论上预示了在热电子等离子体中,等离子体漂移波是最重要的低频不稳定性。
关键词: 相似文献
5.
6.
托卡马克理想磁流体不稳定性的统一描述 (I) 总被引:1,自引:0,他引:1
石秉仁 《核聚变与等离子体物理》2001,21(2):65-72
在与平衡磁面相联系的坐标系下,用剪切阿尔芬波近似给出了统一描述托卡马克等离子体理想磁流体线性运动的本征模方程。利用此方程,可以进一步给出大尺度扰动(扭曲模、低模数气球模、阿尔芬模)和小尺度扰动(高模数气球模、Mercier模)的本征模方程。本文详细讨论了小尺度扰动的本征模方程。 相似文献
7.
从麦克斯韦方程和流体理论出发,推导了填充磁化等离子体慢波结构的基本方程.在大磁场情况下,对等离子体填充盘荷波导的色散特性和耦合阻抗作了研究,结果表明填充等离子体使色散曲线上移,耦合阻抗提高.等离子体填充产生出模式谱非常丰富的周期性低频等离子体模式(TG模式).当等离子体密度增加到一定程度后,场模TM01模的频率范围和TG01模的频率范围相近,两个模式互相耦合产生出新的混合模G1,G2.如果相对论行波管工作在混合模上,将会产生新的工作机理.
关键词:
盘荷波导
等离子体填充
色散特性
相对论行波管 相似文献
8.
本文利用宏观冷流体模型及麦克斯韦方程研究了磁约束在圆柱形导体容器内的弱相对论电子等离子体的宏观非寻常模稳定性,寻出了槽纹扰动下(kz=0)的普遍本征方程,分析中包含平衡自洽场。在低频扰动情况下,简化了本征方程,并仔细研究了电子等离子体在矩形分布下的稳定性质。 相似文献
9.
10.
本文用磁流体理论,导出了包含导电端板“线结”效应的热电子等离子体低频交换模的色散关系,分析了热电子环的稳定作用,求出了稳定性判据。“线结”效应能大大降低交换模的增长率。取热电子密度为零,就得到简单流体等离子体的结果。 相似文献
11.
12.
The question of the sign of the energy of the electrostatic wave which is excited in a beam plasma system is discussed. The relevance of this sign for the existence of an explosively unstable coupling to two positive energy waves is investigated. Weakly explosive instabilities are expected. 相似文献
13.
Liu C.S. Tripathi V.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(1):191-193
A plasma filled backward wave oscillator supports Trivelpiece-Gould (TG) and TM modes. The former can be driven unstable by a relativistic electron beam via Cerenkov interaction or by the plasma return current as two stream instability. This unstable TG mode can parametrically couple to a TM mode via a negative energy beam mode giving rise to an explosive instability 相似文献
14.
We study the effect of the mass and charge dynamics on the collective behaviour of a dusty plasma. It is shown that the finite
non-zero streaming velocity of the dust grains leads to a novel coupling of the dust mass fluctuation with other dynamic variables
of the plasma and the grains. The mass fluctuations causes a collisionless dissipation and provides an alternate channel for
the beam mode instability to occur. Physically the negative energy wave associated with the beam mode couples to the mass
fluctuation induced dissipative medium to produce the instability. We conclude that the higher value of the ion mass density
to the dust mass density ratio reduces the threshold value for the onset of the instability. Its application in the astrophysical
context is discussed. 相似文献
15.
Approximate formulas are derived for the critical density and pressure at which the atoms of hydrogen-like plasmas become ionized due to overlapping of the wave functions. By this mechanism, not only the thermally excited but also the ground state atoms of alkali plasmas become ionized already at moderate pressures. Numerical examples are given for H, Li, Na, K, Rb, and Cs plasmas. It is shown that the (negative) electron-ion interaction energy balances the (positive) thermal energy for sufficiently high electron densities (e.g., n ~ 1020 cm-3 for T ~ 104 K) so that the plasma assumes a cohesive state similar to that of a (liquid) metal. From the quantum effects, the electron exchange energy contributes significantly to this "self-containment" of dense plasmas. 相似文献
16.
Demetre J. Economou 《Applied Surface Science》2007,253(16):6672-6680
Ion-ion plasmas can form in the late afterglow of pulsed discharges or downstream of continuous wave discharges in electronegative gases. In ion-ion plasmas, negative ions replace electrons as the negative charge carriers. In the absence of electrons, ion-ion plasmas behave quite differently compared to conventional electron-ion plasmas. Application of a radio frequency bias to a substrate immersed in an ion-ion plasma can be used to extract alternately positive and negative ions, thereby minimizing charging on device features during micro-device fabrication. Ion-ion plasmas are also important in negative ion sources, dusty plasmas, and the D-layer of the earth's atmosphere. 相似文献
17.
A.B. Shvartsburg 《Physics Reports》1985,125(5):187-252
The present state of research of resonant Joule interactions of collisional plasmas with electromagnetic waves, including both the problems of plasma heating and wave dynamics, is reviewed. The controlled development of non-linear wave processes in gaseous and solid-body plasmas in radiowave and microwave ranges via resonant heating is discussed. The series of thermal bistability effects, produced by electron-temperature hysteresis near Langmuir and cyclotron resonances, is considered. The geometrical resonances of absorption in layered structures and bounded volumes are illustrated. Localization of dissipation phenomena near resonant regions in heterogeneous and anisotropic magnetoplasmas is analyzed. Relativistic and quantum effects in resonant collisional attenuation of waves in a plasma are shown. Some analogous tendencies in Joule wave phenomena are marked in plasmas characterized by very different physical conditions-from laboratory devices up to cosmic objects. 相似文献
18.
Experimental and theoretical studies are made of the consequences of a nonlinear coupling process between pump rf waves and interchange modes in mirror plasmas. It is demonstrated that the interchange-stable operation window exists depending on the applied rf power and gamma=omega(0)/Omega(i), where omega(0) (Omega(i)) is the angular frequency of the applied rf wave (ion cyclotron frequency). Results are shown that the nonlinear wave coupling process gives rise to the operation window near the resonance (gamma approximately equal to 1), which is elucidated by theoretical analyses combined with full rf wave simulations. 相似文献
19.
A theoretical study is made on the generation mechanism of Langmuir mode wave in the presence of kinetic Alfvén wave turbulence
in a magnetized plasma on the basis of plasma-maser interaction. It is shown that a test high frequency Langmuir mode wave
is unstable in the presence of low frequency kinetic Alfvén wave turbulence. The growth of the Langmuir wave occurs due to
direct and polarization coupling terms. Because of the universal existence of the kinetic Alfvén waves in large scale plasmas,
the results have potential importance in space and astrophysical radiation processes. 相似文献
20.
Nejoh Y. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(2):205-209
A new type of nonlinear wave modes which occurs in the electrostatic drift waves in an inhomogeneous magnetized plasma is presented. The author predicts the existence of a new type of spiky solitary wave and an explosive mode with a negative potential as stationary solutions of this equation. These solutions are a consequence of a density gradient and not connected with a temperature gradient. These new nonlinear wave solutions appear to make a step forward in the general scheme of nonlinear normal modes for plasma waves. Using these nonlinear wave modes, the author can explain the solitary structure and the explosive event concerning nonlinear drift waves propagating in space 相似文献