On the Magnitude and Variability of Height Gradients in the Equatorial F Region Vertical Plasma Drifts. Issue 6 (29th June 2019)

• Record Type: Journal Article
• Authors: Shidler, S. A.; Rodrigues, F. S.
• Is Part Of: Journal of geophysical research. Volume 124:Issue 6(2019)
• Page Start: 4916
• Page End: 4925
• Publication Date: 2019-06-29
• Subjects: ionosphere -- electrodynamics -- drifts -- gradients -- equatorial -- Jicamarca; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1029/2019JA026661
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: Previous radar studies have shown that magnitude of the vertical component of equatorial ionospheric E ×B plasma drifts can vary significantly with height, even within main F region altitudes. These studies, however, were limited to few observation days. In order to properly quantify the height variation of equatorial F region vertical drifts, we examined 559 days of measurements made by the incoherent scatter radar of the Jicamarca Radio Observatory between the years of 1986 and 2017. From the observed profiles of vertical plasma drifts, we determined the mean behavior and variability of the height gradients as a function of local time and two distinct solar flux conditions (mean F 10.7 around 80 and 150 SFU). Only observations made under geomagnetically quiet conditions were considered. Our results quantify the enhanced negative height gradients of vertical drifts near sunset that have been reported in the past. More importantly, we also identify and explain an enhancement in positive gradients near sunrise. We discuss the variability of the height gradients in vertical ionospheric E ×B drifts at main equatorial F region heights, and the impact of this variability for satellite observations and studies of ionospheric stability and equatorial spread F . Key Points: The magnitude and variability of gradients in equatorial F region vertical drift profiles are determined from long‐term radar observations We identify an enhancement in the mean gradients around sunrise and propose an explanation for its origin We discuss the impact of the observed drift gradients on satellite observations and studies of ESF