scholarly journals Satellite Measured Ionospheric Magnetic Field Variations over Natural Hazards Sites

2021 ◽  
Vol 13 (12) ◽  
pp. 2360
Author(s):  
Christoph Schirninger ◽  
Hans U. Eichelberger ◽  
Werner Magnes ◽  
Mohammed Y. Boudjada ◽  
Konrad Schwingenschuh ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Natural Hazards ◽  
Field Measurements ◽  
Volcanic Eruptions ◽  
Low Earth Orbit ◽  
Near Surface ◽  
The Earth ◽  
Magnetic Field Measurements ◽  
Spatio Temporal ◽  
Magnetic Field Variations

Processes and threats related to natural hazards play an important role in the evolution of the Earth and in human history. The purpose of this study is to investigate magnetic field variations measured at low Earth orbit (LEO) altitudes possibly associated with earthquakes, volcanic eruptions, and artificial outbursts. We focus on two missions with well equipped magnetometer packages, the China Seismo-Electromagnetic Satellite (CSES) and ESA’s three spacecraft Swarm fleet. After a natural hazards survey in the context of this satellites, and consideration of external magnetospheric and solar influences, together with spacecraft interferences, wavelet analysed spatio-temporal patterns in ionospheric magnetic field variations related to atmospheric waves are examined in detail. We provide assessment of the links between specific lithospheric or near surface sources and ionospheric magnetic field measurements. For some of the diverse events the achieved statistical results show a change in the pattern between pre- and post-event periods, we show there is an increase in the fluctuations for the higher frequency (smaller scales) components. Our results are relevant to studies which establish a link between space based magnetic field measurements and natural hazards.

The effect of plasmaspheric material on magnetopause reconnection

2020 ◽  
Author(s):  
Stephen Fuselier ◽  
Stein Haaland ◽  
Paul Tenfjord ◽  
David Malaspina ◽  
James Burch ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Temperature ◽  
Magnetic Reconnection ◽  
Plasma Wave ◽  
Outer Part ◽  
Field Measurements ◽  
Ion Composition ◽  
The Earth ◽  
Magnetospheric Multiscale ◽  
Magnetic Field Measurements

<p>The Earth’s plasmasphere contains cold (~eV energy) dense (>100 cm<sup>-3</sup>) plasma of ionospheric origin. The primary ion constituents of the plasmasphere are H<sup>+ </sup>and He<sup>+</sup>, and a lower concentration of O<sup>+</sup>. The outer part of the plasmasphere, especially on the duskside of the Earth, drains away into the dayside outer magnetosphere when geomagnetic activity increases. Because of its high density and low temperature, this plasma has the potential to modify magnetic reconnection at the magnetopause. To investigate the effect of plasmaspheric material at the magnetopause, Magnetospheric Multiscale (MMS) data are surveyed to identify magnetopause crossings with the highest He<sup>+</sup>densities. Plasma wave, ion, and ion composition data are used to determine densities and mass densities of this plasmaspheric material and the magnetosheath plasma adjacent to the magnetopause. These measurements are combined with magnetic field measurements to determine how the highest density plasmaspheric material in the MMS era may affect reconnection at the magnetopause.</p>

scholarly journals Electrojet estimates from mesospheric magnetic field measurements

2020 ◽  
Author(s):  
Karl Laundal ◽  
Jesper Gjerloev ◽  
Sam Yee ◽  
Slava Merkin ◽  
Heikki Vanhamäki ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Low Earth Orbit ◽  
Measurement Technology ◽  
Earth Orbit ◽  
Long Distance ◽  
Small Satellites ◽  
Spatiotemporal Characteristics ◽  
Magnetic Field Measurements ◽  
The Magnetic Field

<p>The auroral electrojet is traditionally measured remotely with magnetometers on ground or in low Earth orbit. The long distance, more than 100 km, means that smaller scale sizes are not detected. Because of this, the spatiotemporal characteristics of the electrojet are not known. Recent advances in measurement technology give hope of remote detections of the magnetic field in the mesosphere, very close to the electrojet. We present a prediction of the magnitude of these disturbances, inferred from the spatiotemporal characteristics of magnetic field-aligned currents. We also discuss how a constellation of small satellites carrying the Microwave Electrojet Magnetogram (MEM) instrument (Yee et al., 2020), could be used to essentially image the equivalent current at unprecedented spatial resolution. </p>

scholarly journals Electrojet estimates from mesospheric magnetic field measurements

2021 ◽  
Author(s):  
Karl Laundal ◽  
Jeng-Hwa Yee ◽  
Jesper Gjerloev ◽  
Heikki Vanhamäki ◽  
Jone Reistad ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Field Measurements ◽  
Low Earth Orbit ◽  
Measurement Technology ◽  
Magnetic Field Sensors ◽  
Spatiotemporal Characteristics ◽  
Spatial Coverage ◽  
Magnetic Field Measurements ◽  
The Magnetic Field ◽  
Current Representation

<p>The auroral electrojet is traditionally measured remotely with magnetometers on ground or in low Earth orbit (LEO). The sparse spatial coverage of measurements, combined with a vertical distance (~100 km to ground and typically >300 km to LEO satellites) means that smaller scale sizes cannot be detected.  Because of this, our understanding of the spatiotemporal characteristics of the electrojet is incomplete. Recent advances in measurement technology allow us to overcome these limitations by multi-point remote detections of the magnetic field in the mesosphere, very close to the electrojet. We present a theoretical prediction of the magnitude of these disturbances, inferred from the spatiotemporal characteristics of magnetic field-aligned currents. We further discuss how the Electrojet Zeeman Imaging Explorer (EZIE) satellites that will carry Zeeman magnetic field sensors will be used to essentially image the equivalent current at unprecedented spatial resolution.  The electrojet imaging is demonstrated by combining carefully simulated measurements with a spherical elementary current representation using a novel inversion scheme.  This new capability will allow us to finally resolve long-standing controversies such as – what is the substorm current wedge configuration?</p>

A Machine Learning technique for ULF wave classification in Swarm magnetic field measurements

2021 ◽  
Author(s):  
Alexandra Antonopoulou ◽  
George Balasis ◽  
Constantinos Papadimitriou ◽  
Zoe Boutsi ◽  
Omiros Giannakis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Machine Learning ◽  
Field Measurements ◽  
Data Availability ◽  
Machine Learning Technique ◽  
Ulf Wave ◽  
The Earth ◽  
Swarm Satellites ◽  
Magnetic Field Measurements ◽  
Learning Technique

<p>Ultra-low frequency (ULF) magnetospheric plasma waves play a key role in the dynamics of the Earth’s magnetosphere and, therefore, their importance in Space Weather studies is indisputable. Magnetic field measurements from recent multi-satellite missions are currently advancing our knowledge on the physics of ULF waves. In particular, Swarm satellites have contributed to the expansion of data availability in the topside ionosphere, stimulating much recent progress in this area. Coupled with the new successful developments in artificial intelligence, we are now able to use more robust approaches for automated ULF wave identification and classification. The goal of this effort is to use a machine learning technique to classify ULF wave events using magnetic field data from Swarm. We construct a Convolutional Neural Network that takes as input the wavelet power spectra of the Earth’s magnetic field variations per track, as measured by each one of the three Swarm satellites, aiming to classify ULF wave events in four categories: Pc3 wave events, background noise, false positives, and plasma instabilities. Our primary experiments show promising results, yielding successful identification of 90% accuracy. We are currently working on producing larger datasets, by analyzing Swarm data from mid-2014 onwards, when the final constellation was formed.</p>

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