ABSTRACT
A typical example of plasma is a highly or fully ionized gas. The name "plasma" is also often given to a weakly ionized gas and to the electron gas or the electron liquid in semiconductors and metals. A suitable illustration is the rotation of the plane of polarization when transverse electromagnetic waves propagate in plasma in the direction of the magnetic field. The wave causes a change in the velocity distribution that occurs comparatively easily in the "tail". The result is that collisionless absorption is changed and can disappear altogether if the distribution function undergoes an appropriate variation under the effect of the wave. Wave propagation in inhomogeneous plasmas is therefore an important subject. Other important areas of plasma physics concern relativistic plasmas, the non-steady-state plasmas, various nonlinear phenomena, and plasma behaviour in strong magnetic fields, taking account of nonlinearity of the vacuum.
