Do localized electric fields cause the structure of the aurora?



The aurora, which has fascinated mankind for centuries, is characterized by thin, discrete auroral arcs, also referred to as auroral curtains and draperies. Their latitudinal thickness is often only a few hundred meters or less, as measured by Akasofu [1961], Maggs and Davis [1968], and Borovsky et al. [1991]. Explaining this thin structure still remains one of the major mysteries of auroral research. Borovsky [1993] has recently shown that no currently accepted theory can account for this remarkable feature of the aurora. It is therefore relevant to reexamine the underlying assumptions for these theories, virtually all of which are premised on localized electric fields in the high-altitude auroral zone being the cause of the structure of the aurora.