OICC Press Journal of Theoretical and Applied Physics 2251-7235 18 5 2024 10 26 Evolution of electromagnetic soliton during laser-plasma interaction in an electron-positron-ion plasma having constant density gradient 1 10 10.57647/j.jtap.2024.1805.56 EN Gaurav Kumar Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, India https://orcid.org/0000-0002-8575-4236 Hitendra K. Malik Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, India https://orcid.org/0000-0002-9432-8140 Journal Article 2024 10 26 Laser propagation in an electron-positron-ion (EPI) plasma medium having a constant densitygradient is studied for the soliton evolution in the presence of a parallelly applied strong magneticfield. In a nonlinear regime, laser-plasma interaction forms an electron density hill that movesbackward due to the density gradient. This hill localizes laser energy by the mechanism ofresonance absorption (ωl =ωpe) and remains stable for a longer period, qualifying for the evolutionof electromagnetic soliton. The position of the soliton from where it starts moving backwarddepends on the slope of the linear density variation. If the slope increases, then the position of thesoliton is closer to the plasma boundary (x = 0). Another interesting property of the soliton is thatits height decreases, and width increases as the temperature of plasma species rises. We simulatethis phenomenon of electromagnetic soliton evolution in 1-D and 2-D by using Particle-In-Cell(PIC) simulation using the EPOCH-4.17.10.