Wave generation in the aurora

Wave generation mechanisms by a number of free energy sources in the magnetosphere are discussed. These include the temperature difference between the plasma sheet and the tail lobes, the temperature anisotropy, and field aligned currents. It is shown that a number of wave-modes can be generated via a Weibel-type instability by the above free energy sources, also the production of Langmuir waves can be created by ion-acoustic turbulence. Various wave-particle interaction mechanisms are presented as possible processes for the production of high energy electrons which are responsible for the aurora. (author)