Head-on collisions of ion-acoustic Korteweg-de Vries/modified Korteweg-de Vries solitons in a magnetized quantum electron-positron-ion plasma

The head-on collisions of ion-acoustic solitary waves (IASWs) in a dense magnetized quantum plasma are investigated. The two-sided Korteweg-de Vries (KdV) equations in generic case as well as the two-sided modified Korteweg-de Vries (mKdV) equations in a special case are obtained, the analytical phase shifts and the trajectories after the head-on collisions of two IASWs in a three species quantum plasma are derived by using the extended version of Poincar,-Lighthill-Kuo (PLK) method for both the situations. We provide the theoretical predictions about the existence of compressive and rarefactive IASWs in the model. We observe that in generic case collisions are possible among the same polarity solitons, whereas in the special case collisions are possible among the same or opposite polarities solitons. Moreover the colliding phase shifts are significantly affected by the quantum diffraction parameter, by the square of the ratio of ion gyrofrequency to ion plasma frequency and by obliqueness of propagation. The important observations of this manuscript are that the waves reach a maximum amplitude which is the superposition of the initial amplitudes and they suffer a time delay during their collision. The plasma parameter values for white dwarfs are taken for discussion.