Salahuddin M, Saleem H, Saddiq M
Pakistan Atomic Energy Commission, P. O. Box 1114, Islamabad-44000, Pakistan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Sep;66(3 Pt 2B):036407. doi: 10.1103/PhysRevE.66.036407. Epub 2002 Sep 25.
Ion-acoustic envelope solitons in a collisionless unmagnetized electron-positron-ion plasma are studied. The Krylov-Bogoliubov-Mitropolsky perturbative technique is used to obtain the nonlinear Schrödinger equation. The critical wave number for the modulational instability depends upon the concentration of different species and the temperature ratios of electrons and positrons. In the limiting case of zero positron concentration we recover the previous results of electron-ion plasma. It is found that a small concentration of ions in the electron-positron plasmas can change the dynamics of the system significantly. The ions can introduce slow time and long spatial scales in the plasmas. Thus the electron-positron plasmas become richer in linear and nonlinear wave dynamics.
研究了无碰撞、无磁化的电子 - 正电子 - 离子等离子体中的离子声包络孤子。采用Krylov - Bogoliubov - Mitropolsky微扰技术得到非线性薛定谔方程。调制不稳定性的临界波数取决于不同粒子种类的浓度以及电子和正电子的温度比。在正电子浓度为零的极限情况下，我们得到了电子 - 离子等离子体的先前结果。研究发现，电子 - 正电子等离子体中少量的离子会显著改变系统的动力学。离子可以在等离子体中引入慢时间和长空间尺度。因此，电子 - 正电子等离子体在线性和非线性波动动力学方面变得更加丰富。
