Journal ArticleDOI
The F-Region Gravity and Pressure Gradient Current Systems: A Review
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TLDR
The ionospheric gravity and pressure-gradient current systems are most prominent in the low-latitude $F$676 -region due to the plasma density enhancement known as the equatorial ionization anomaly (EIA), which builds up during the day and lasts well into the evening.Abstract:
The ionospheric gravity and pressure-gradient current systems are most prominent in the low-latitude $F$
-region due to the plasma density enhancement known as the equatorial ionization anomaly (EIA). This enhancement of plasma density which builds up during the day and lasts well into the evening supports a toroidal gravity current which flows eastward around the Earth in the $F$
-region during the daytime and evening, and eventually returns westward through the $E$
-region. The existence of pressure-gradients in the EIA region also gives rise to a poloidal diamagnetic current system, whose flow direction acts to reduce the ambient geomagnetic field inside the plasma. The gravity and pressure-gradient currents are among the weaker ionospheric sources, with current densities of a few $\mbox{nA/m}^{2}$
, however they produce clear signatures of about 5–7 nT in magnetic measurements made by low-Earth orbiting satellites. In this work, we review relevant observational and modeling studies of these two current systems and present new results from a 3D ionospheric electrodynamics model which allows us to visualize the entire flow pattern of these currents throughout the ionosphere as well as calculate their magnetic perturbations.read more
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Journal ArticleDOI
Challenges to Understanding the Earth's Ionosphere and Thermosphere
Rod Heelis,Astrid Maute +1 more
TL;DR: In this paper, the authors discuss the challenges to understanding and description of the coupled plasma and neutral gas that make up the ionosphere and thermosphere (I•T) and discuss some of the challenges that must be addressed to understand how the I•T responds to coupling from the surrounding regions of geospace.
Journal ArticleDOI
Lower-Thermosphere-ionosphere (LTI) quantities : Current status of measuring techniques and models
Minna Palmroth,Minna Palmroth,Maxime Grandin,Theodoros Sarris,Eelco Doornbos,Stelios Tourgaidis,Anita Aikio,Stephan Buchert,Mark A. Clilverd,Iannis Dandouras,Roderick A. Heelis,Alex Hoffmann,Nickolay Ivchenko,Guram Kervalishvili,David J. Knudsen,Anna Kotova,Hanli Liu,David M. Malaspina,Günther March,Aurélie Marchaudon,Octav Marghitu,Tomoko Matsuo,Wojciech Jacek Miloch,Therese Moretto-Jørgensen,Dimitris Mpaloukidis,Nils Olsen,Konstantinos Papadakis,Robert F. Pfaff,Panagiotis Pirnaris,Christian Siemes,Claudia Stolle,Jonas Suni,Jose van den IJssel,Pekka T. Verronen,Pekka T. Verronen,Pieter Visser,Masatoshi Yamauchi +36 more
TL;DR: In this paper, the authors present a review of the state of the art in measuring the lower-thermosphere ionosphere (LTI) either in situ or by several different remote-sensing methods.
Journal ArticleDOI
Magnetic Signatures of Ionospheric and Magnetospheric Current Systems During Geomagnetic Quiet Conditions—An Overview
Nils Olsen,Claudia Stolle +1 more
TL;DR: In this paper, the authors provide an overview of ionospheric and magnetospheric sources and illustrate their magnetic signatures with Swarm satellite observations, focusing on geomagnetic quiet conditions.
Local Estimation of the Earth's Core Magnetic Field
TL;DR: In this article, two local techniques for estimating the Earth's outer core generated magnetic field are described and implemented using satellite data from the Swarm and CHAMP satellite missions, which can be used to quantify the uncertainty and resolution of these estimates.
Journal ArticleDOI
Magnetic Field Data Correction in Space for Modelling the Lithospheric Magnetic Field
TL;DR: In this paper, the authors review methods most commonly used in geomagnetism to identify and then to correct for the external perturbation fields at satellite altitudes and discuss some perspectives for improvements of external field correction techniques relying on statistical or more explicit assumptions about the geographical distribution as well as the shape and strengths of the external magnetic field structures.
References
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