Solitarywave evolution inmagnetized plasma under ionization effect

Abstract

Summary form only given. Nonlinearity and dispersive properties of the plasma play an important role for the evolution and propagation of the solitary waves. If these solitary waves retain their shapes after collision with each other, then they are referred to as solitons. The soliton structure can trap plasma particles and convect them over large distances. Therefore, they are useful in the transportation of energy and anomalous particles from one region to the another in laboratory, astrophysical and space related plasmas. Washimi and Taniuti [1] were the first to show that the solitary wave propagation in plasmas can be described by the Korteweg-deVries (KdV) equation. After this pioneering work, many researchers made attempts for studying the soliton propagation in different plasma models [2-7]. In most of the real situations, we encounter inhomogeneous plasmas and in that case the KdV equation is found to be modified. Then it becomes very difficult to solve the modified KdV equation due to its variable coefficients. In the recent years, theoretical attempts have been made to study the solitons in plasmas having density gradient [4 . 7]. Although these investigations were made in almost real situations, an important component of ionization has not been taken into consideration. Therefore, in the present article, we have focused on the effect of ionization on the solitary wave evolution and its propagation in a magnetized plasma having density gradient. We obtain dispersion relation using Reductive Perturbation Method (RPM) in order to examine the possible modes in the plasma. Then we derive relevant KdV equation, which is found to be modified with the variable coefficients and also carries an additional term due to the density gradient. We solve this equation using sine-cosine method and then investigate the solitary wave propagation under the effects of magnetic field, density inhomogeneity and ionization rate. The main focus is kept on the contribution of the ionization rate to this solitary wave (soliton) evolution and the corresponding density structures are examined.