Experimental evidence of ion acoustic soliton chain formation and validation of nonlinear fluid theory
Experimental evidence of ion acoustic soliton chain formation and validation of nonlinear fluid theory
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DOI：
10.1063/1.4810794
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发表时间：
2013-06
影响因子：
2.2
通讯作者：
A. Kakad;Y. Omura;B. Kakad
中科院分区：
文献类型：
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作者：
A. Kakad;Y. Omura;B. Kakad
通过假设系统长度较大，对电子-离子等离子体中离子声孤子（IA）平行于磁场传播进行了一维流体模拟。为了模拟初始密度扰动（IDP），我们采用KdV孤子型解决方案。我们的模拟表明，IA孤子的产生机制依赖于IDP的波长。短波长的IDP演化为两个反向传播的相同的IA孤子，而长波长的IDP通过一个破波过程发展为两个不可区分的多个IA孤子链。波破碎发生在接近静电能量超过电子流体的动能的一半的时刻。波浪破碎的振幅和起始时间取决于IDP的特性。IDP的强度控制孤立子链中IA孤子的数量。在模拟中估计的IA孤子在稳定传播过程中的速度、宽度和振幅与非线性流体理论符合得很好。该流体模拟首次证实了广泛应用于实验室和空间等离子体孤立波研究的一般非线性流体理论的有效性。
We perform one-dimensional fluid simulation of ion acoustic (IA) solitons propagating parallel to the magnetic field in electron-ion plasmas by assuming a large system length. To model the initial density perturbations (IDP), we employ a KdV soliton type solution. Our simulation demonstrates that the generation mechanism of IA solitons depends on the wavelength of the IDP. The short wavelength IDP evolve into two oppositely propagating identical IA solitons, whereas the long wavelength IDP develop into two indistinguishable chains of multiple IA solitons through a wave breaking process. The wave breaking occurs close to the time when electrostatic energy exceeds half of the kinetic energy of the electron fluid. The wave breaking amplitude and time of its initiation are found to be dependent on characteristics of the IDP. The strength of the IDP controls the number of IA solitons in the solitary chains. The speed, width, and amplitude of IA solitons estimated during their stable propagation in the simulation are in good agreement with the nonlinear fluid theory. This fluid simulation is the first to confirm the validity of the general nonlinear fluid theory, which is widely used in the study of solitary waves in laboratory and space plasmas.