Comparison of high-latitude and mid-latitude ionospheric electric fields

Abstract

Simultaneous measurements of the F region electric field by the incoherent scatter technique have been made at Chatanika, Alaska (65.1°N, 147.5°W), and Millstone Hill, Massachusetts (42.6°N, 71.5°W), on July 18–19 and August 7–8, 1973. Good correlation was observed in the time variation of the perpendicular electric field at the two stations. Magnetic conditions for these days were relatively quiet with some variations evident from the high‐latitude magnetograms and the Chatanika radar, but no distinct effect appeared on the mid‐latitude magnetograms. Since magnetospheric electric fields are thought to be the source of high‐latitude electric fields such as those observed at Chatanika, the good correlation in the perpendicular electric field for the two stations indicates that the magnetospheric originated electric fields have an appreciable effect down to at least L = 3.2.

Statistical Study of Nightside Quiet Time Midlatitude Ionospheric Convection

“…However, the consistency in the flow direction in the premidnight sector indicates that penetration is taking place at middle latitudes even under relatively quiet magnetic conditions. This conclusion was also reached by Carpenter and Kirchhoff (1975) through their examination of the electric field variations at Millstone Hill and Chatanika (Λ =∼65.5 ∘ ). Wand and Evans (1981b) concluded that during quiet time conditions the evening southward electric field (eastward drift) at Millstone Hill could be due to the penetration electric field, but the eastward electric field (poleward drift) represents the dynamo electric field only.…”

“…In the absence of geomagnetic disturbance one might naively expect the F region ion convection to follow the pattern of the background neutral winds; however, previous studies have not found this to be the case (Buonsanto et al, ). Likewise, the occurrence of penetration electric fields is mostly invoked under geomagnetically disturbed conditions (e.g., Blanc et al, ; Buonsanto et al, ; Yeh et al, ), but some studies have also reported the presence of penetration electric fields under quiet time conditions (e.g., Carpenter & Kirchhoff, ; Heelis & Coley, ; Lejosne & Mozer, ; Wand & Evans, ). Understanding the relative importance of these two mechanisms in driving plasma convection in the midlatitude region has been an important topic of ongoing research for decades, and this study is part of that effort, focusing on the subauroral midlatitude plasma convection under quiet geomagnetic conditions.…”

Joint two-dimensional observations of ground magnetic and ionospheric electric fields associated with auroral zone currents. 2. Three-dimensional current flow in the morning sector during substorm recovery.

“…We contend that the subauroral southward equivalent current flow of about 40 nT cannot be explained as equatorward ionospheric currents. The inference of equatorward Hall current in this region is unrealistic, since subauroral eastward electric fields of the order of 0.2-0.3mVm-1 (e. g., CARPENTER and KIRCHHOFF, 1975;CARPENTER and SEELY, 1976;CARPENTER et al, 1979) are not strong enough to drive a Hall current of the order of 40mVm-1 (see KAMIDE and BREKKE, 1975, for estimating the ionospheric current density) without assuming an unrealistically large Hall conductivity (about 130-200 mho in comparison with normal values of less than 2 mho; cf. .…”

Recent Developments in Our Knowledge of Inner Magnetosphere‐Ionosphere Convection

“…Finally, Buonsanto et al (1993) and Buonsanto and Witasse (1991) derived average convection patterns for three seasons using Millstone Hill ISR measurements and found a predominantly westward flow in the nightside midlatitude region, with a strong seasonal dependence. This inconsistent behavior suggests that neutral winds may not be the 10.1029/2018JA025914 dominant drivers of midlatitude ion convection and perhaps other factors such as PEFs can be important even during quiet geomagnetic conditions (Carpenter & Kirchhoff, 1975;Heelis & Coley, 1992;Wand & Evans, 1981). These early studies revealed the limitations in our understanding of quiet time subauroral convection by demonstrating that neutral winds cannot completely explain the observed patterns.…”