Showing papers by "Arthur D. Richmond published in 1973"
TL;DR: In this paper, physical features of the equatorial electrojet were examined with the aid of a numerical model which includes neutral-air winds and the two-stream instability, and it was found that the model currents and resultant magnetic variations are relatively unaffected by assuming the parallel conductivity, σ 0, to be infinite.
238 citations
TL;DR: In this article, a numerical physical model was developed to reproduce the basic features of the observed electrojet, but certain discrepancies suggest that the assumptions of the model or the conductivity distributions used may be inaccurate.
85 citations
TL;DR: In this paper, the authors used coupled numerical models of the global ionospheric dynamo and of the equatorial electrojet to simulate the magnetic variations observed at four universal times on a quiet day.
72 citations
TL;DR: In this article, a detailed investigation of the relationship between the equatorial anomaly and the strength of the Equatorial electrojet was made using data for all of 1958 in four longitude sectors.
63 citations
TL;DR: In this paper, the authors show that a small-scale convective motion can be generated by the presence of thermal plasma in the magnetosphere, with a growth rate on the order of 1.9 × 10−3 sec−1 at night, creating turbulence which tends to destroy the steep plasma density gradient.
Abstract: Significant small-scale convective motions can be generated by the presence of thermal plasma in the magnetosphere. An isolated plasma-filled flux tube at L = 4, of density 3 ×108 m−3 and temperature 3000 K, can convect away from the earth at a velocity on the order of 0.7 RE hr−1 at night, due to the electric field it creates. An interchange instability occurs at the plasmapause, with a growth rate on the order of 1.9 × 10−3 sec−1 at night, creating turbulence which tends to destroy the steep plasma density gradient. This instability can explain the gradual decrease of the density gradient observed during periods of decreasing magnetic activity. In order to maintain a steep density gradient, three possibilities are discussed: (a) reduction of the instability growth rate due to enhanced ionospheric conductance; (b) reduction of the growth rate due to the presence of radiation belt plasma and/or a sharp temperature increase at the plasmapause; and (c) rapid radial convergence of large-scale flow due to the presence of an Alfven layer at the plasmapause. The self-induced convective motions may also be important in the production and/or redistribution of small-scale irregularities of thermal plasma observed both inside and outside the plasmapause.
46 citations