High-frequency nonlinear electromagnetic waves propagating in an unmagnetized plasma

The propagation of electromagnetic waves in plasma is a crucial topic, as it pertains to both natural plasma environments and the advancement of practical technologies, such as communications, radar systems, and plasma diagnostics. This study derives a novel two-dimensional nonlinear Schrödinger equation (NLSE) to describe the nonlinear electromagnetic waves propagating in an unmagnetized plasma. The results demonstrate the existence of a dark nonlinear envelope electromagnetic wave in such plasma conditions. This derivation of the NLSE provides a useful framework for researchers to extend NLSE formulations to various plasma systems. Furthermore, this study reveals for the first time that a general dark nonlinear envelope electromagnetic wave can exist in an unmagnetized plasma, where the angle between the propagation direction of the background wave and that of the envelope wave packet can be arbitrary. The validation through particle-in-cell simulations ensures the reliability of the theoretical results. This novel understanding opens up new avenues for the application of such waves in areas ranging from astrophysical phenomena to advanced military and civilian technologies. The outcomes of this research also have potential applications in fusion research, space plasma studies, radar communication, and laser–plasma interactions.