Particle-In-Cell simulations of an electron beam: stability and wave emissions

During peaks of magnetospheric activity, energetic electrons trapped in the inner magnetosphere can precipitate in the lower ionosphere due to electromagnetic wave activity. Such waves can be generated naturally or artificially, for instance, through the emission of plasma beams. In this work, we study waves generated by electron beams emitted parallel to the magnetic field using fully kinetic Particle-In-Cell simulations. To this end, we use the heavily parallelized SMILEI code. To reduce the weight of the simulation, we take advantage of the rotational symmetry of the problem and use a cylindrical frame, which reduces the simulation to a 2D problem with cylindrical symmetry. We investigate the impact of the beam characteristics (such as beam density, frequency, length, etc.) on the wave generation, and the structural evolution of the beam as it exchanges energy with the electromagnetic fields and interacts with the background plasma.