ABSTRACT

One of the earliest and most extensive applications of the theory of electromagnetic waves in ionized gases was to the propagation of radio waves in the ionosphere. The equations of magneto-ionic theory are those of Maxwell together with equations of motion of the hydrodynamic type. The linear approximation is a very familiar mathematical technique. A plasma model of much wider theoretical interest arises when it is supposed that there is a pervading magnetostatic field. The main general effect produced by a magnetic field is to compel the ionized gas to act in its response to electromagnetic waves as an anisotropic medium. When a collisionless electron-ion gas is pervaded by a magnetostatic field the motion of the positive ions can in certain circumstances be important. For two charged particles a long range electromagnetic interaction between them is always present, and the concept of a collision is less precise.