The radiation and propagation characteristics of a plasma column is theoretically studied in isothermal/non-isothermal regimes. The Boltzmann and Maxwell equations are employed to derive the radial profile of the electron temperature, electron density and the field components. It is found that by increasing the plasma density the plasma system goes toward the non-isothermal regime. It is shown that for the high values of the electron density, the isothermal approach would be violated and it must be replaced with the non-isothermal approach. This model is applicable to the plasma column with azimuthally symmetric plasma density. The present results are important from practical point of view and can be used in design and tuning of the plasma antennas. تفاصيل المقالة

AbstractDust lattice modes are studied in a hexagonal two-dimensional lattice in plasma crystal, including paramagnetic dust particles. The gradients of magnetic fields, electric fields, and dust charge and also the interaction of dipole-dipole take into account. These gradients modify the levitation condition and affect the frequencies of dust lattice waves. The coupling between in-plane and out-of-plane modes gives rise to the hybrid mode, which is always an unstable mode. However, intersection of the in-plane mode with other modes does not result in mode-coupling instability. تفاصيل المقالة

AbstractWeak ion-acoustic solitary waves (IASWs) in an unmagnetized quantum plasmas having two-fluid ions and fluid electrons are considered. Using the one-dimensional quantum hydrodynamics model and then the reductive perturbation technique, a generalized form of nonlinear quantum Korteweg-de Vries (KdV) equation governing the dynamics of weak ion acoustic solitary waves is derived. The effects of ion population, warm ion temperature, quantum diffraction, and polarity of ions on the nonlinear properties of these IASWs are analyzed. It is found that our present plasma model may support compressive as well as rarefactive solitary structures. Furthermore, formation and characteristics properties of IA double layers in the present bi-ion plasma model are investigated. The results of this work should be useful and applicable in understanding the wide relevance of nonlinear features of localized electro-acoustic structures in laboratory and space plasma, such as in super-dense astrophysical objects [24] and in the Earth’s magnetotail region (Parks [43]. The implications of our results in some space plasma situations are discussed. تفاصيل المقالة

AbstractThe basic features of nonlinear ion acoustic (IA) waves are theoretically studied in a superthermal electron–positron–ion (e–p–i) plasma with weakly transverse perturbation. A three-dimensional Kadomtsev–Petviashvili (KP) equation governing evolution of weakly nonlinear IA waves is derived by means of a reductive perturbation method. The energy integral equation is used to study the existence domain of the localized structures. It is found that deviation from thermodynamics equilibrium increases the existence domain of solitary solution and also makes the IA solitary structure more spiky. The ion concentration has an important effect on the existence domain of solitary solution, as for low ion density the primitive domain reduces significantly. تفاصيل المقالة

We consider a new type of integrable coupled nonlinear Schrodinger (CNLS)equations proposed by our self [submitted to Phys. Plasmas (2011)]. The explicitform of soliton solutions are derived using the Hirota's bilinear method.We show that the parameters in the CNLS equations only determine the regionsfor the existence of bright and dark soliton solutions. Finally, throughthe linear stability analysis, the modulational instability condition is given. تفاصيل المقالة