Oblique collisional effects of dust acoustic waves in unmagnetized dusty plasma

Abstract

Effects of oblique collisions of the dust acoustic (DA) waves in dusty plasma are studied by considering unmagnetized fully ionized plasma. The plasma consists of inertial warm negatively charged massive dusts, positively charged dusts, superthermal kappa distributed electrons, and isothermal ions. The extended Poincaré–Lighthill–Kuo (ePLK) method is employed for the drivation of two-sided Korteweg–de Vries (KdV) equations (KdVEs). The KdV soliton solutions are derived by using the hyperbolic secant method. The effects of superthermality index of electrons, temperature ratio of isothermal ion to electron, and the density ratio of isothermal ions to negatively charged massive dusts on nonlinear coefficients are investigated. The effects of oblique collision on amplitude, phase shift, and potential profile of right traveling solitons of DA waves are also studied. The study reveals that the new nonlinear wave structures are produced in the colliding region due to head-on collision of the two counter propagating DA waves. The nonlinearity is found to decrease with the increasing density ratio of ion to negative dust in the critical region. The phase shifts decrease (increase) with increasing the temperature ratio of ion to electron (κ e). The hump (compressive, κ e < κ ec) and dipshaped (rarefactive, κ e > κ ec) solitons are produced depending on the angle (θ) of oblique collision between the two waves.

Long-time evolution of charged grains in plasma under harmonic external force and after being withdrawn

“…[12,20,21] Thus, when the distance between the grains is large (small), the interaction force is attractive (repulsive). [16][17][18][19][20][21] It should be mentioned that other grain-grain interaction models [3,4,12,13] can also lead to qualitatively similar results, as long as the model includes both attractive and repulsive interaction regime.…”

“…[1] The grain-grain interaction force, which is attractive at larger distances due to a unique graingrain shadowing effect, and repulsive at smaller distances due to electrostatic repulsion, plays an important role in the growing and evolving of dust grains, and can lead to many interesting, unusual, as well as practical phenomena. [3,4,[11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Recently it has been shown that by tailoring the external force one can obtain controllable compact structures such as dust-grain crystals, [26,27] and the time required to reach the cluster state decreases with external force increasing. [28][29][30][31][32][33] Although what happens after the external force has been withdrawn can be important in many applications, [1] it has not been investigated.…”