Samad Sobhanian

This study presents a two-dimensional fluid model for simulating DC corona discharge in a point-to-plane configuration, implemented using the Least Squares Finite Element Method (LSFEM). The model accounts for electrons, positive ions, and negative ions, with transport described by the drift–diffusion approximation and coupled self-consistently to the electric field through Poisson’s equation. Field-dependent ionization, attachment, and recombination processes are incorporated to capture the essential physics of negative corona discharges. The LSFEM framework enables stable and accurate resolution of steep gradients and complex boundary conditions, while maintaining computational efficiency over long simulation times. Results reveal the temporal and spatial evolution of charged species, the redistribution of the electric field under space-charge effects, and the transition toward a quasi-steady state dominated by negative ion accumulation. Comparisons with previous numerical and experimental studies demonstrate that the proposed approach reproduces key features of corona behavior, offering a robust and efficient tool for both physical understanding and engineering design of corona-based systems.

This article investigates various methods for enabling the transmission of radio waves at frequencies lower than the plasma frequency. These methods include the injection of solid dielectric materials into the plasma and the use of a magnetic window to reduce plasma density for radio communication. The material and dimensions of injected particles in altering the transmission rate of radio signals have also been investigated. These methods can help reduce radio blackout during hypersonic flights and when spacecraft re-entering the Earth's atmosphere. However, there is a need for precise adjustment of electrodes and magnets to prevent increasing the weight of spacecraft and to configure magnetic field lines for the response of electrons to electromagnetic waves.

In this paper, the effect of the material and distance of the substrate on the characteristics of gamma alumina nanopowder coated by plasma spray method are investigated. For this purpose alumina nanopowder were coated on the two types of stainless steel and Pyrex glass substrates using a plasma torch. Morphological characteristics ...

Nonlinear dynamical behavior of an ion with finite temperature in a driven plasma ion-sheath has been studied by a numerical solution of fluid equations. Using the concepts of the nonlinear dynamical system theory, the conditions under which the dynamical behavior of the ion becomes chaotic have been investigated. The numerical results have revealed that there is an order-chaos-order transition in the isothermal plasma ion-sheath due to the external oscillating electric field. In the case of an adiabatic ion-sheath, even with a strong external electric field, no chaotic motion has appeared.

Using the Sagdeev pseudo-potential method, the oblique propagation of dust-ion acoustic solitary waves is studied in a magnetized dusty plasma. By considering non-thermal distribution of electrons, the related pseudo-potential is obtained using the Poisson equation. The behavior of the wave is investigated for some ranges of parameters. It is demonstrated that the increase in ion density, lz, β, and also δ1 can lead to the increases in the width and amplitude of the pseudo-potential, while any increase of a2, the coefficient that describes the first nonlinear term in the G(ϕ), increases the amplitude of the V(ϕ).