Basics of Laser-Plasma Interaction: a Selection of Topics

A short, tutorial introduction to some basic concepts of laser-plasma interactions at ultra-high intensities is given. The selected topics include a) elements of the relativistic dynamics of an electron in electromagnetic fields, including the ponderomotive force and classical radiation friction; b) the "relativistic" nonlinear optical transparency and self-focusing; c) the moving mirror concept and its application to light sail acceleration and high harmonic generation, with a note on related instabilities; d) some specific phenomena related to the absorption of energy, kinetic momentum and angular momentum from the laser light.