WAVES IN A PLASMA

Plasma is a complex fluid that supports many plasma wave modes. Restoring forces include kinetic pressure and electric and magnetic forces. Wave phenomena are important for heating plasmas, instabilities and diagnostics etc. In vacuum, there is only one wave mode the electromagnetic wave with ω/k = c and having oscillating E and B components perpendicular to k. In air, both sound waves and electromagnetic waves propagate. In plasma, both electrostatic waves and electromagnetic waves will propagate. In the former case, the electric field perturbation associated with the wave is parallel to the wave propoagation direction E//k so that there are no magnetic perturbations associated with the wave: