Rapid changes and near-stationarity of the geomagnetic field during a polarity reversal

Nature ◽  
1987 ◽  
Vol 330 (6144) ◽  
pp. 145-148 ◽  
Author(s):  
Carlo Laj ◽  
Sylvie Guitton ◽  
Catherine Kissel
Keyword(s):  
Geomagnetic Field ◽  
Polarity Reversal ◽  
Rapid Changes

scholarly journals Geomagnetic jerks characterization via spectral analysis

Solid Earth ◽  
2012 ◽  
Vol 3 (1) ◽  
pp. 131-148 ◽  
Author(s):  
B. Duka ◽  
A. De Santis ◽  
M. Mandea ◽  
A. Isac ◽  
E. Qamili
Keyword(s):  
Time Series ◽  
Geomagnetic Field ◽  
Synthetic Data ◽  
Spatial Evolution ◽  
Spectral Techniques ◽  
The Third ◽  
Rapid Changes ◽  
Geomagnetic Jerks ◽  
Third Derivative ◽  
Harmonic Power

Abstract. In this study we have applied spectral techniques to analyze geomagnetic field time-series provided by observatories, and compared the results with those obtained from analogous analyses of synthetic data estimated from models. Then, an algorithm is here proposed to detect the geomagnetic jerks in time-series, mainly occurring in the eastern component of the geomagnetic field. Applying such analysis to time-series generated from global models has allowed us to depict the most important space-time features of the geomagnetic jerks all over the globe, since the beginning of XXth century. Finally, the spherical harmonic power spectrum of the third derivative of the main geomagnetic field has been computed from 1960 to 2002.5, bringing new insights to understand the spatial evolution of these rapid changes of the geomagnetic field.

scholarly journals Midlatitude cooling caused by geomagnetic field minimum during polarity reversal

2013 ◽  
Vol 110 (4) ◽  
pp. 1215-1220 ◽  
Author(s):  
Ikuko Kitaba ◽  
Masayuki Hyodo ◽  
Shigehiro Katoh ◽  
David L. Dettman ◽  
Hiroshi Sato
Keyword(s):  
Geomagnetic Field ◽  
Polarity Reversal

scholarly journals Causes and Consequences of Geomagnetic Field Collapse

2020 ◽  
pp. 60-76
Author(s):  
J. Marvin Herndon
Keyword(s):  
Geomagnetic Field ◽  
Ohmic Heating ◽  
Electrical Current ◽  
Magnetic Polarity ◽  
Self Control ◽  
Polarity Reversal ◽  
Rift System ◽  
Stable Operation ◽  
East African Rift System ◽  
Charge Particle

Consequences of the next geomagnetic field collapse, concomitant with a magnetic polarity reversal or excursion, have been greatly underestimated as based upon a widely-accepted, but physically-impossible geoscience paradigm. The underlying causes of geomagnetic field collapse are inexplicable in that flawed paradigm wherein geomagnetic field production is assumed to be produced in the Earth’s fluid core. Here I review the causes and consequences of geomagnetic field collapse in terms of a new geoscience paradigm, called Whole-Earth Decompression Dynamics, specifically focusing on nuclear fission georeactor generation of the geomagnetic field and the intimate connection between its energy production and the much greater stored energy of protoplanetary compression. The nuclear georeactor is subject to a staggering range and variety of potential instabilities. Yet, its natural self-control mechanism allows stable operation without geomagnetic reversals for times longer than 20 million years. Geomagnetic reversals and excursions occur when georeactor sub-shell convection is disrupted. Disrupted sub-shell convection can occur due to (1) major trauma to Earth such as an asteroid collision or (2) change in the charge particle flux from the sun or change in the ring current either of which can induce electrical current into the georeactor via the geomagnetic field causing ohmic-heating that can potentially disrupt sub-shell convection. Further, humans could deliberately or unintentionally disrupt sub-shell convection by disrupting the charge-particle environment across portions of the geomagnetic field by nuclear detonations or by heating the ionosphere with focused electromagnetic radiation. The use of electromagnetic pulse weapons is potentially far more devastating to humanity than previously imagined, and should be prohibited. During the next polarity reversal or excursion, increased volcanic activity may be expected in areas fed by georeactor heat, such as the East African Rift System, Hawaii, Iceland, and Yellowstone in the USA. One potentially great risk is triggering the eruption of the Yellowstone super-volcano.

scholarly journals Elevated paleomagnetic dispersion at Saint Helena suggests long-lived anomalous behavior in the South Atlantic

2020 ◽  
Vol 117 (31) ◽  
pp. 18258-18263 ◽  
Author(s):  
Yael A. Engbers ◽  
Andrew J. Biggin ◽  
Richard K. Bono
Keyword(s):  
Geomagnetic Field ◽  
Anomalous Behavior ◽  
Magnetic Polarity ◽  
South Atlantic ◽  
Polarity Reversal ◽  
The South ◽  
Geomagnetic Secular Variation ◽  
Core Dynamics ◽  
Geocentric Axial Dipole ◽  
Magnetic Polarity Reversal

Earth’s magnetic field is presently characterized by a large and growing anomaly in the South Atlantic Ocean. The question of whether this region of Earth’s surface is preferentially subject to enhanced geomagnetic variability on geological timescales has major implications for core dynamics, core−mantle interaction, and the possibility of an imminent magnetic polarity reversal. Here we present paleomagnetic data from Saint Helena, a volcanic island ideally suited for testing the hypothesis that geomagnetic field behavior is anomalous in the South Atlantic on timescales of millions of years. Our results, supported by positive baked contact and reversal tests, produce a mean direction approximating that expected from a geocentric axial dipole for the interval 8 to 11 million years ago, but with very large associated directional dispersion. These findings indicate that, on geological timescales, geomagnetic secular variation is persistently enhanced in the vicinity of Saint Helena. This, in turn, supports the South Atlantic as a locus of unusual geomagnetic behavior arising from core−mantle interaction, while also appearing to reduce the likelihood that the present-day regional anomaly is a precursor to a global polarity reversal.

scholarly journals Using spectral analysis to detect singular events such as jerks in the geomagnetic field time series

2011 ◽  
Vol 3 (2) ◽  
pp. 615-654
Author(s):  
B. Duka ◽  
A. De Santis ◽  
M. Mandea ◽  
A. Isac ◽  
E. Qamili
Keyword(s):  
Time Series ◽  
Spectral Analysis ◽  
Geomagnetic Field ◽  
Synthetic Data ◽  
Global Scale ◽  
Spherical Harmonic Analysis ◽  
Global Models ◽  
Spectral Techniques ◽  
Rapid Changes ◽  
Geomagnetic Jerks

Abstract. In this study we have applied two spectral techniques in terms of Fourier and wavelet analysis to geomagnetic field time series and compared the results with those obtained from analogous analyses to synthetic data. Then, an algorithm has been proposed to detect the geomagnetic jerks in time series, mainly being considered by the Eastern component secular variation. Applying such analysis to time series generated from global models has allowed us to depict the most important space-time features of the geomagnetic jerks on global scale, since the beginning of XXth century. Finally, a spherical harmonic analysis of the secular acceleration power spectrum has been computed since 1960 to 2000, bringing new insights in understanding these rapid changes of the geomagnetic field and their origin.

scholarly journals Toward a possible next geomagnetic transition?

2013 ◽  
Vol 13 (12) ◽  
pp. 3395-3403 ◽  
Author(s):  
A. De Santis ◽  
E. Qamili ◽  
L. Wu
Keyword(s):  
Critical Point ◽  
Geomagnetic Field ◽  
Outer Core ◽  
Reverse Time ◽  
Geomagnetic Reversal ◽  
Rapid Changes ◽  
Global Mean Sea Level ◽  
Logarithmic Functions ◽  
Near Future ◽  
Global Mean

Abstract. The geomagnetic field is subject to possible reversals or excursions of polarity during its temporal evolution. Considering that: (a) in the last 83 million yr the typical average time between one reversal and the next (the so-called chron) is around 400 000 yr, (b) the last reversal occurred around 780 000 yr ago, (c) more excursions (rapid changes in polarity) can occur within the same chron and (d) the geomagnetic field dipole is currently decreasing, a possible imminent geomagnetic reversal or excursion would not be completely unexpected. In that case, such a phenomenon would represent one of the very few natural hazards that are really global. The South Atlantic Anomaly (SAA) is a great depression of the geomagnetic field strength at the Earth's surface, caused by a reverse magnetic flux in the terrestrial outer core. In analogy with critical point phenomena characterized by some cumulative quantity, we fit the surface extent of this anomaly over the last 400 yr with power law or logarithmic functions in reverse time, also decorated by log-periodic oscillations, whose final singularity (a critical point tc) reveals a great change in the near future (2034 ± 3 yr), when the SAA area reaches almost a hemisphere. An interesting aspect that has recently been found is the possible direct connection between the SAA and the global mean sea level (GSL). That the GSL is somehow connected with SAA is also confirmed by the similar result when an analogous critical-like fit is performed over GSL: the corresponding critical point (2033 ± 11 yr) agrees, within the estimated errors, with the value found for the SAA. From this result, we point out the intriguing conjecture that tc would be the time of no return, after which the geomagnetic field could fall into an irreversible process of a global geomagnetic transition that could be a reversal or excursion of polarity.

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