Effect of variable dust size, charge and mass on dust acoustic solitary waves in nonextensive magnetized plasma

Effects of variable dust size, mass and charge on the characteristics of nonlinear dust acoustic solitary waves (DASW) in a two-temperature ion dusty plasma have been studied analytically. Plasma ions are assumed to be Maxwellian while plasma electrons are nonextensively distributed. Mass and electrical charge of dust particles are assumed to be proportional to their size. Plasma is embedded in an external magnetic field with variable direction. The Zakharov-Kuznetsov equation was derived using reductive perturbation method, and its solitary answers were extracted. Dispersion relation of DASW shows that this wave may generate in plasma only if the nonextensivity coefficient, q, is positive. For all allowed magnitudes of c (the ratio of the largest dust radius to smallest dust radius) and q, only rarefactive solitons may be formed in plasma. Effect of variable dust size on the width and amplitude of DASW is noticeable when c is smaller than 3. Both the width and amplitude of DASW increase with increasing c, and with increasing the nonextensivity of plasma, effect of variable size increases. Results show that increasing the strength of external magnetic field leads to localization of DASW while both the width and amplitude of DASW are under the influence of the direction of the external magnetic field simultaneously.