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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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Book ChapterDOI
01 Jan 2018
TL;DR: A conceptual discussion of plasma is first presented in this article, and various space plasma environments are discussed along with a brief introduction to the history of space research, and some key plasma parameters such as density, gyrofrequency, and temperature, and characteristics (collective motion, quasi-neutrality) are discussed concisely.
Abstract: A plasma is an electrically conducting quasi-neutral gas mainly composed of charged particles that exhibit collective motion. The vast majority of observable universe consists of plasma. Closer to Earth, i.e., in the solar-terrestrial environment, the solar wind, the magnetosphere, and the ionosphere are the most studied plasma environments. Plasma processes are greatly influenced by ambient electromagnetic fields and, in analogy with neutral planetary atmospheres, waves are continuously generated in plasmas and their propagation and interaction influence the structure and the evolution of plasma. A naturally occurring magnetic field environment is the geomagnetic field, which has already been detected four centuries ago. In this introductory chapter, a conceptual discussion of plasma is first presented. Then, various space plasma environments are discussed along with a brief introduction to the history of space research. Finally, some key plasma parameters such as density, gyrofrequency, and temperature, and characteristics (collective motion, quasi-neutrality) are discussed concisely.

163 citations

Journal ArticleDOI
TL;DR: In this article, a quasi-steady model of global lower atmospheric electricity is presented, which considers thunderstorms as dipole electric generators that can be randomly distributed in various regions and that are the only source of atmospheric electricity and includes the effects of orography and electrical coupling along geomagnetic field lines in the ionosphere and magnetosphere.
Abstract: A quasi-steady model of global lower atmospheric electricity is presented. The model considers thunderstorms as dipole electric generators that can be randomly distributed in various regions and that are the only source of atmospheric electricity and includes the effects of orography and electrical coupling along geomagnetic field lines in the ionosphere and magnetosphere. The model is used to calculate the global distribution of electric potential and current for model conductivities and assumed spatial distributions of thunderstorms. Results indicate that large positive electric potentials are generated over thunderstorms and penetrate to ionospheric heights and into the conjugate hemisphere along magnetic field lines. The perturbation of the calculated electric potential and current distributions during solar flares and subsequent Forbush decreases is discussed, and future measurements of atmospheric electrical parameters and modifications of the model which would improve the agreement between calculations and measurements are suggested.

162 citations

V. L. Patel1
01 Apr 1975
TL;DR: In this paper, the authors studied the geomagnetic storm events during 1966 and 1970 by using simultaneous interplanetary magnetic field and plasma parameters and found that the field fluctuations in By, Bz and Ey and Ez are present in the initial phase.
Abstract: Twenty-one geomagnetic storm events during 1966 and 1970 were studied by using simultaneous interplanetary magnetic field and plasma parameters. Explorer 33 and 35 field and plasma data were analyzed on large-scale (hourly) and small-scale (3 min.) during the time interval coincident with initial phase of the geomagnetic storms. The solar-ecliptic Bz component turns southward at the end of the initial phase, thus triggering the main phase decrease in Dst geomagnetic field. When the Bz is already negative, its value becomes further negative. The By component also shows large fluctuations along with Bz. When there are no clear changes in the Bz component, the By shows abrupt changes at the main phase onet. On the small-scale behavior of the magnetic field and electric field (E=-VxB) studied in details for the three events, it is found that the field fluctuations in By, Bz and Ey and Ez are present in the initial phase. These fluctuations become larger just before the main phase of the storm begins. In the largescale behavior field remains quiet because the small scale variations are averaged out.

162 citations

Journal ArticleDOI
TL;DR: In this paper, the characteristics of the central plasma sheet under all levels of geomagnetic activity were investigated and the results showed that the central sheet consists of plasma with high thermal energy (several keV) but low bulk speeds.
Abstract: The University of Iowa Lepedea on board ISEE 1 is used to investigate the characteristics of the central plasma sheet under all levels of geomagnetic activity. Positive ion responses from 1 eV to 45 keV are used in this study. All the periods during 1978 when the central plasma sheet is encountered are included. This study excludes all boundary layer samples. The results of this study show that the central plasma sheet consists of plasma with high thermal energy (several keV) but low bulk speeds. This remains true even during high geomagnetic activity. The main effect of increasing activity is heating of the plasma sheet, preferentially at the high-latitude boundaries.

162 citations

Journal ArticleDOI
TL;DR: In this article, a review of the analysis of low-latitude geomagnetic variation during magnetic storms or substorms is made, and the contribution of the partial ring current system to low latitude geOMagnetic variations is discussed, concluding that the main contribution to the longitudinal ΔH asymmetry in middle and low latitudes comes primarily from the Birkeland current and neither from the partial rings current in the equatorial plane nor from the auroral electrojet.
Abstract: In recent years the longitudinal asymmetry of the ring current in the magnetosphere encircling the earth has been advocated to explain the geomagnetic field variation in middle and low latitudes. Direct observations of particles and magnetic field by means of satellites in the magnetosphere have given some supporting evidence for the existence of partial ring current in the magnetosphere. In this article a review is made of the analysis of low-latitude geomagnetic variation during magnetic storms or substorms, and the contribution of the partial ring current system to low-latitude geomagnetic variations is discussed. After examining the magnetic effect of each part of the partial ring current system, i.e., (1) the equatorial ring current in a limited longitude range, (2) the Birkeland (field aligned) current in the magnetosphere connecting the equatorial plane and the ionosphere, and (3) the current in the ionosphere, including an electrojet along the auroral zone or oval, we conclude that the main contribution to the longitudinal ΔH asymmetry in middle and low latitudes (H is the horizontal component of the geomagnetic field) comes primarily from the Birkeland current and neither from the partial ring current in the equatorial plane nor from the auroral electrojet. Therefore the models of partial ring current need to be modified so as not to overemphasize the ring-form current closure in the equatorial plane. This article explains the reason for the above conclusions and gives some necessary considerations for interpreting the geomagnetic variations in low latitudes during magnetic storms and substorms and on quiet days.

162 citations


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