Auroral Studies : Observations and Simulations

There have been so many optical observations of aurora so far, but there have not been adequate quantitative interpretations of their causality between the source (auroral energetic particles), the resultant auroral volume emission rates, and the fields. Difficulties of these studies are in the fact that (1) observationally, we have not obtained simultaneously and quantitatively physical quantities of the source, the resultant emission and the field, and (2) theoretically, we have not fully understood the physical processes of auroral emissions. Recently we have performed some experiments which give us some physical parameters related to these problems. On the other hand, the computer simulation schemes to calculate the photoemission rates from the source particles have been developed. In this review paper, I will present some examples of the auroral observations and give a talk what kinds of theoretical works we are now investigating; Particularly following five themes are discussed. Rocket experiment, spectroscopic observation, stereoscopic observation, satellite observations and computer simulations.