Preplasma effects on the emission directions of energetic electrons in relativistic laser-solid interactions

摘要

Motivated by recent experimental observations of fast electron jets emitted along the target surface in intense laser-solid interactions with a large incident angle of the laser pulse, we simulate electron emissions by two-dimensional particle-in-cell simulations. When there is no preplasma in advance of the main laser pulse, electrons are emitted dominantly along the target surface. However, when there is preplasma. electron emission changes to the target normal. This difference originates from the different absorption mechanisms and different Coulomb electrostatic fields and self-generated magnetic fields induced in front of the target for the two cases.