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Earth's magnetic field

About: Earth's magnetic field is a research topic. Over the lifetime, 20360 publications have been published within this topic receiving 446747 citations. The topic is also known as: magnetic field of Earth & geomagnetic field.


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Journal ArticleDOI
TL;DR: In this paper, the authors used ground magnetograms to determine the onset times of two substorms that occurred while the Ogo 5 satellite was inbound on the midnight meridian through the cusp region of the geomagnetic tail (the region of rapid change from taillike to dipolar field).
Abstract: The sequence of events occurring throughout the magnetosphere during a substorm has not been precisely determined. This paper introduces a collection of papers that attempts to establish this sequence for two substorms on August 15, 1968. Data from a wide variety of sources are used, the major emphasis being changes in the magnetic field. In this paper we use ground magnetograms to determine the onset times of two substorms that occurred while the Ogo 5 satellite was inbound on the midnight meridian through the cusp region of the geomagnetic tail (the region of rapid change from taillike to dipolar field). We conclude that at least two worldwide substorm expansions were preceded by growth phases. Probable beginnings of these phases were at 0330 and 0640 UT. However, the onset of the former growth phase was partially obscured by the effects of a preceding expansion phase around 0220 and a possible localized event in the auroral zone near 0320 UT. The onsets of the corresponding expansion phases were 0430 and 0714 UT. Further support for these determinations is provided by data discussed in the subsequent notes.

113 citations

Journal ArticleDOI
TL;DR: The terrestrial thermosphere and ionosphere form the most variable part of the Earth's atmosphere as discussed by the authors, and the reason for the extreme variability of the terrestrial ionosphere is its rapid response to external forcing from various sources, i.e., thesolar ionizing flux, energetic charged particles and electric fields imposed via the interaction between the solar wind, magnetosphere and the ionosphere, as well as coupling from below (meteorological influences) by the upward propagating, broad spectrum, internal atmospheric waves (planetary waves, tides, gravity waves) generated in thestr
Abstract: The terrestrial thermosphere and ionosphere form the most variable part of theEarth's atmosphere. Because our society depends on technological systems thatcan be affected by thermospheric and ionospheric phenomena, understanding,monitoring and ultimately forecasting the changes of the thermosphere–ionosphere system are of crucial importance to communications, navigation and the exploration of near-Earth space. The reason for the extreme variability of the thermosphere–ionosphere system isits rapid response to external forcing from various sources, i.e., thesolar ionizing flux, energetic charged particles and electric fields imposed via the interaction between the solar wind, magnetosphere and ionosphere, as well as coupling from below (“meteorological influences”) by the upward propagating, broad spectrum,internal atmospheric waves (planetary waves, tides, gravity waves) generated in thestratosphere and troposphere. Thunderstorms, typhoons, hurricanes, tornadoes andeven seismological events may also have observable consequences in the ionosphere.The release of trace gases due to human activity have the potential to cause changes inthe lower and the upper atmosphere.A brief overview is presented concerning the discoveries and experimentalresults that have confirmed that the ionosphere is subject to meteorologicalcontrol (especially for geomagnetic quiet conditions and for middle latitudes).D-region aeronomy, the winter anomaly of radiowave absorption, wave-liketravelling ionospheric disturbances, the non-zonality and regional peculiaritiesof lower thermospheric winds, sporadic-E occurrence and structure, spread-Fevents, the variability of ionospheric electron density profiles and Total ElectronContent, the variability of foF2, etc., should all be considered in connection withtropospheric and stratospheric processes. “Ionospheric weather”, as a part of spaceweather, (i.e., hour-to-hour and day-to-day variability of the ionospheric parameters)awaits explanation and prediction within the framework of the climatological, seasonal,and solar-cycle variations.

113 citations

Journal ArticleDOI
TL;DR: In this paper, worldwide changes in earth magnetic field determined by examination of magnetic field and interplanetary plasma data for solar wind near the earth near the Earth were determined by examining the magnetic field of the Earth near the Sun.
Abstract: Worldwide changes in earth magnetic field determined by examination of magnetic field and interplanetary plasma data for solar wind near earth

113 citations

Journal ArticleDOI
TL;DR: In this article, the authors used incoherent scatter radar observations made at the Jicamarca Radio Observatory between 1970 and 2003 to study and model empirically the equatorial zonal plasma drifts near the F region peak using Bernstein polynomials as base functions.
Abstract: [1] We use extensive incoherent scatter radar observations made at the Jicamarca Radio Observatory between 1970 and 2003 to study and model empirically the equatorial zonal plasma drifts near the F region peak using Bernstein polynomials as base functions. Our quiet-time model results confirm that the daytime drifts are westward and are nearly season and solar cycle independent. The nighttime drifts are eastward, have larger magnitudes, and increase strongly with solar flux, particularly near equinox and December solstice. Enhanced geomagnetic activity drives small eastward perturbation drifts during the day and much larger westward disturbance drifts at night. The nighttime drift perturbations are largest near midnight and increase strongly with solar flux near equinox and December solstice but are essentially absent near June solstice. The Jicamarca zonal disturbance drifts can be largely accounted for by disturbance dynamo electric fields with a dominant time delay of about 3-15 hours following enhanced geomagnetic activity. In the postmidnight sector, there are also smaller westward disturbance drifts associated with time delays of about 15-24 hours and perhaps even longer. Our results strongly suggest that the longitudinal dependence of both the quiet and disturbed equatorial nighttime zonal drifts varies with season.

113 citations

Journal ArticleDOI
TL;DR: In this paper, a simple equilibrium theory of ionization transport in the ionosphere is described which predicts a tendency for thin layers of overdense ionization (sporadic E layers) to form in the E-region.
Abstract: A simple equilibrium theory of ionization transport in the ionosphere is described which predicts a tendency for thin layers of overdense ionization (sporadic E layers) to form in the E-region. Such layers can be produced by the dominance of any of five mechanisms of ionization convergence. Three of these mechanisms involve the neutral wind shear and two involve the neutral wind. The theory assumes that ambipolar diffusion of the electrons and heavy positive ions takes place under the influence of the forces due to neutral collisions and the geomagnetic field. The layer formation tendency is strongest for the principal part of the wind shear convergence mechanism in the lower E-region at those altitudes where the neutral vorticity is antiparallel to the geomagnetic field, land in the upper E-region where the neutral vorticity is perpendicular to the geomagnetic field in the westward (eastward) sense in the northern (southern) geomagnetic hemisphere. The layer formation tendency is strongest for t...

113 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023657
20221,202
2021477
2020553
2019604
2018581