Optical-Particle Characteristics of the Polar Cusp

Abstract

The use of extended ground based optical measurements of the dayside cusp has yielded much information on the general characteristics and dynamics of this region of the auroral oval. They show a region of stable (mostly 6300A) emission during the noon period but which becomes more active and marked by frequent short lived enhancements of 5577A emission beginning about 1 hour after local magnetic noon. It can be inferred that the enhancements are due to more energetic electron influx. Two rocket flights across the cusp region, one into post-noon conditions (VB-03 at 0004:58 UT on Dec. 6, 1977) and a second into conditions more noon-like (IVB-38 at 23:14:58 UT on Dec. 6, 1981), have yielded electron data which are compared with simultaneous ground-based photometric measurements at 6300A and 5577A.