Ionospheric Conductance Spatial Distribution During Geomagnetic Field Reversals

Zossi, Bruno S.; Elı́as, Ana G.; Fagre, Mariano

doi:10.1002/2017ja024925

Cited by 12 publications

(10 citation statements)

References 50 publications

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“…This configuration leads to flux enhancement of energetic particles in this area, which increases conductivity at the bottomside of the ionosphere. According to Zossi et al (2018), Hall conductivity is highest around the SAA longitudes. We interpret that the peak occurrence of PWD over the SAA longitudes is partly caused by the high Hall conductivity, which is favorable for mode conversion and ducting of Pc1 waves (Fujita & Tamao, 1988;Yoshikawa & Itonaga, 2000).…”

Section: Seasonal Dependence and Relationship With Plasma Densitymentioning

confidence: 99%

Statistical Analysis of Pc1 Wave Ducting Deduced From Swarm Satellites

et al. 2021

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Section: Seasonal Dependence and Relationship With Plasma Densitymentioning

confidence: 99%

Statistical Analysis of Pc1 Wave Ducting Deduced From Swarm Satellites

et al. 2021

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“…In this work, the polar caps' location and shape are determined for different geomagnetic field configurations during reversals. These scenarios were recently considered by Zossi et al (2018) in a study of the ionospheric Hall and Pedersen conductances. The method used to estimate the polar caps is described in Section 2, followed by the obtained results in Section 3.…”

Section: Introductionmentioning

confidence: 99%

Polar caps during geomagnetic polarity reversals

Zossi

Fagre

Amit

et al. 2018

Geophysical Journal International

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Changes in the Earth's magnetic field can deeply modify the polar caps and auroral zones, which are the regions of most frequent precipitation of energetic particles. The present field is characterized by a dominant dipole plus weaker multipolar components. The field varies greatly in time, with the most drastic changes being polarity reversals that take place on average every ∼200 000 yr. During a polarity transition the field magnitude may diminish to about 10 per cent of its value prior to the reversal due to a decreasing dipolar component and by becoming mostly multipolar in nature. Polar caps depend on the geomagnetic field configuration so changes in their morphology are expected as a consequence of the variation and reversal of this field. We model polar caps' location by considering a superposition of the internal geomagnetic field and a uniform external field and then following the open field lines to the Earth's surface. Polar caps' location and shape for different magnetic field reversal scenarios are analysed in this work. Two polar caps near the present dipole axis intersection with the Earth's surface prevail for a dipole decrease to a certain extent, below which the southern hemisphere polar cap moves to mid-latitudes. An axial dipole collapse gives a pair of polar caps both at mid-latitudes of the southern hemisphere, while in a dipole rotation scenario the polar caps reside at the equator. If reversals occur due to an energy cascade from the dipole to higher degrees, more than two polar caps may appear. In our energy cascade scenario, four polar caps at various latitudes of both hemispheres prevail. These results indicate that during reversals auroral zones may reach mid-and low-latitude regions, and the atmosphere may become more vulnerable to the direct effect of energetic particle precipitation. This vulnerability is particularly striking at the southern hemisphere where reversed flux patches appear on the core-mantle boundary and weak intensity characterizes the present field at the Earth's surface.

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“…Zossi et al () go further in time and analyze conductances variation expected during several Earth's magnetic field reversal scenarios, considering extremely weak and much less uniform fields. In addition to a global conductance increase, the spatial gradient becomes stronger at some regions.…”

Section: Introductionmentioning

confidence: 99%

Pedersen Ionic Contribution in Different Time Scales

2019

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Pedersen conductivity is one of the main parameters in atmospheric electrodynamics, magnetosphere‐ionosphere‐thermosphere coupling, and several other geophysical processes. It is determined by the collision frequency between charged and neutral components and the Earth's magnetic field intensity through the gyrofrequency. This work analyzes the contribution of different ionic species to the variability of Pedersen conductance in time scales from hours to years within the period 1964–2008 based on the results of various atmospheric and ionospheric models. The main results are (1) there is a positive correlation between O+ density and Pedersen conductance, (2) Pedersen conductance of F layer has a larger increase with the solar activity than that of E layer, (3) Pedersen conductance has a long‐term trend that is determined by Earth's magnetic field intensity and electron density, and (4) at midlatitudes trends are mainly governed by the Earth's magnetic field and modulated by the electron density, while at high latitudes both are important.

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Ionospheric Conductance Spatial Distribution During Geomagnetic Field Reversals

Cited by 12 publications

References 50 publications

Statistical Analysis of Pc1 Wave Ducting Deduced From Swarm Satellites

Statistical Analysis of Pc1 Wave Ducting Deduced From Swarm Satellites

Polar caps during geomagnetic polarity reversals

Pedersen Ionic Contribution in Different Time Scales

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