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In the presence of an applied static and uniform magnetic field, a cylindrical Kadomtsev-Petviashivili equation is derived for a relativistic electromagnetic solitary wave propagating in collisionless plasma consisting electrons, positrons, and ions in the case of weak relativistic limit. This equation is solved in a stationary frame to obtain explicit expression for the velocity, amplitude and width of solitons. The amplitude of the solitary wave has a maximum value at a critical αc of the ratio of the ion equilibrium density to the electron one, and it increases as the applied magnetic field becomes larger. 相似文献
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外加电场对光折变高阶响应影响的微扰分析 总被引:2,自引:2,他引:0
应用微扰展开法了“跳跃模型”给出了空间电荷场前三阶分量随时间,外加电场等变化的解析表达式,同时讨论了外加电场对各阶空间电荷场建立的影响,当扩散与外加电场可比拟时,外加电场对空间电荷场的影响不大,随着空间电荷场阶数的提高,其达到最大饱和值所需的外加电磁越小,在外加电场作用下,空间电荷场各阶分量随时间呈振荡衰减,直到达到饱和,外加是场越大,振荡越强烈,周期越短,在考虑高阶分量的贡献后,空间电荷场的振荡 相似文献
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The electronic structures and magnetic properties of SmCo7 xMx (M=Ti, Si, Zr, Hf, Cu, B, Ag, Ga, Mn) compounds are investigated by using a spin-polarized MS-X.α method. The results show that the long-range ferromagnetic order is determined by a stronger 3d-5d interaction, rather than the traditional RKKY interaction, and the effects of doping element M on 3d-5d coupling are negligible in Sm-Co-based compounds. The nonmagnetic dopant Si atoms have a larger effect on the moments of 2e site although they preferably occupy the Co 3g sites, which results in the stronger uniaxial anisotropy of this compound. Analysis of the formation energies indicates that 5d-element doped compounds are more stable than other dopants, and furthermore, they have a higher Curie temperature above room temperature, which will be in favor of their potential application as high-temperature permanent magnets. 相似文献
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Two-dimensional relativistic electromagnetic dromion-like soliton in a cold transparent plasma
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By using a standard multiple scale method, a Davey--Stewartson (DS) equation
has been derived and also applied to a multi-dimensional analytical
investigation on the interaction of an ultra-intense laser pulse with a cold
unmagnetized transparent electron-ion plasma. The regions of instability are
found by considering the modulation instability of a plane wave solution of
the DS equation. The DS equation is just of the Davey--Stewartson 1 (DS1) type
and admits a dromion solution, i.e. a two-dimensional (2D) dromion soliton
decaying exponentially in all spatial directions. A 2D relativistic
electromagnetic dromion-like soliton (2D REDLS) is derived for a vector
potential. 相似文献
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