The origin of the solitary waves in the Earth's magnetosphere and the solar wind, particularly close to the magnetic reconnection regions, is still an open question. For that purpose, we used the fluid model to obtain the mechanism behind the formation of solitary waves in space plasmas with a variety of components. Our findings reveal that at the separatrix of the magnetic reconnection in the Earth's magnetotail, the counter-ejected electron beam leads to a broadening of the pulse amplitude. While increasing the electron beam positive velocity causes a bit increase in the soliton amplitude. Moreover, we observed that the soliton profile is very sensitive to the plasma parameters like density and temperature. The calculated electric field using the current model and the measured electric field in the Earth's magnetosphere and solar wind is highlighted.