الفهرس 
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Abstract
The aim of this study is to reveal the propagation of nonlinear waves in plasma, one of those waves are ion acoustic gardner solitons and double layers in magnetized electron-positronion quantum plasma. Through our paper, the nonlinear propagation of ion-acoustic Gardner solitons (GSs) and double layers (DLs) in electron-positron-ion (EPI) plasma in the presence of an external static magnetic field has been examined. The Korteweg–de Vries (KdV), modified KdV (mKdV), and Gardner equations have been derived by the reductive perturbation technique It is seen that the amplitude, polarity, speed, width of such solitons are significantly modified by the species densities and by the obliquity angle. For example, the phase speed is found to decrease with the increasing of obliquity angle of the wave propagation. Also Compressive or rarefactive KdV solitons are obtained, but only compressive solitons are obtained in the mKdV case, wherever Gardner positive and negative DLs exist This study show significance modifications of the basic properties of the wave solutions and the results could be useful for understanding the wave features in dense quantum plasmas or astrophysical plasmas such as white dwarfs, neutron stars, micro and nano-electronic devices and intense laser-solid matter interaction experiments as an examples of laboratory plasmas.