Ionospheric precursors of earthquakes from satellites

2021 ◽  
Author(s):  
Angelo De Santis ◽  
Saioa A. Campuzano ◽  
Gianfranco Cianchini ◽  
Domenico Di Mauro ◽  
Dedalo Marchetti ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Random Distribution ◽  
Earthquake Magnitude ◽  
Quiet Time ◽  
Earthquake Forecast ◽  
Simple Scheme ◽  
Precursors Of Earthquakes ◽  
Space Distance ◽  
Space Approach

<p>In-situ magnetic field and electron density, as observed by Swarm and CSES satellites, are analyzed to identify possible anomalies in geomagnetic quiet time with respect to the ionospheric background. To avoid detecting possible anomalies induced by auroral activity we investigate regions between +50 and -50 degrees in magnetic latitude. Then a superposed epoch and space approach is applied to this anomaly dataset with respect to their time and space distance from shallow M5.5+ earthquakes occurred in about last 6 years. A comparison with analogous homogeneous random distribution of anomalies shows that the real anomaly concentrations found before the occurrence of earthquakes are statistically significant. In addition, we find that, in general, the anticipation times of the ionospheric precursors scale with the earthquake magnitude, confirming the validity of the Rikitake law for ionospheric signals, previously valid for ground precursors. We also find that the anomaly duration seems to depend on the magnitude of the impending earthquake. Finally, we propose a simple scheme of potential earthquake forecast on the base of the previously mentioned characteristics.</p>

Statistical analysis of Swarm satellite data for assessing the effectiveness of ionospheric precursors of earthquakes

2020 ◽  
Author(s):  
Angelo De Santis ◽  
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Maximum Concentration ◽  
Random Distribution ◽  
Real Data ◽  
Satellite Mission ◽  
The Real ◽  
Random Deviation ◽  
Precursors Of Earthquakes ◽  
Swarm Satellite

<p>Analysing ionospheric electron density and magnetic field data from several years of the <em>Swarm</em> three-satellite mission we define a dataset of anomalies statistically.  We then use a superposed epoch approach to study the possible relation with a corresponding dataset of earthquakes occurred in the same space-time domain. Two statistical quantities <em>d</em> and <em>n</em> are then established comparing the statistics of the real analyses with simulations to assess the effectiveness of the largest concentrations of anomalies as ionospheric precursors. In detail, <em>d</em> would show how much the real maximum concentration is above the expected typical maximum concentration of a random anomaly distribution; while <em>n</em> value measures how much the largest concentration deviates with respect a typical random deviation: the larger are the <em>d</em> and <em>n</em> values, the more the results of the analysis applied to real data deviate from randomness. The best cases for which the real analyses are well distinct from random simulations are selected when <em>d</em>≥1.5, because the anomaly density is equal to or larger than 50% of random distribution, and <em>n</em>≥4, because the probability to be random is equal to or less than 0.1%.  This is the case of Y magnetic field component with a search in the Dobrovolsky area around each considered earthquake epicentre. The electron density is slightly less effective in the correlation with earthquakes, but still better than a homogeneous random distribution of anomalies.</p>

Tuning the Magnetic Alignment of Cellulose Nanocrystals from Perpendicular to Parallel Using Lepidocrocite Nanoparticles

2019 ◽  
Author(s):  
Valentina Guccini ◽  
Sugam Kumar ◽  
Yulia Trushkina ◽  
Gergely Nagy ◽  
Christina Schütz ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Cellulose Nanocrystals ◽  
Small Angle Neutron Scattering ◽  
Lower Amount ◽  
Magnetic Alignment ◽  
Polarized Optical Microscopy ◽  
Parallel Orientation ◽  
Weak Magnetic Fields

The magnetic alignment of cellulose nanocrystals (CNC) and lepidocrocite nanorods (LpN), pristine and in hybrid suspensions has been investigated using contrast-matched small-angle neutron scattering (SANS) under in situ magnetic fields (0 – 6.8 T) and polarized optical microscopy. The pristine CNC (diamagnetic) and pristine LpN (paramagnetic) align perpendicular and parallel to the direction of field, respectively. The alignment of both the nanoparticles in their hybrid suspensions depends on the relative amount of the two components (CNC and LpN) and strength of the applied magnetic field. In the presence of 10 wt% LpN and fields < 1.0 T, the CNC align parallel to the field. In the hybrid containing lower amount of LpN (1 wt%), the ordering of CNC is partially frustrated in all range of magnetic field. At the same time, the LpN shows both perpendicular and parallel orientation, in the presence of CNC. This study highlights that the natural perpendicular ordering of CNC can be switched to parallel by weak magnetic fields and the incorporation of paramagnetic nanoparticle as LpN, as well it gives a method to influence the orientation of LpN.<br>

Aligned Packaging of in-situ Grown CsPbBr3 Nanorods within Polystyrene Nanofibers for Enhanced Polarized Luminescence Properties

2021 ◽  
Author(s):  
Hui Fu ◽  
Huilin Hou ◽  
Zhi Fang ◽  
Chaoyi Chen ◽  
Weiyou Yang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Luminescence Properties ◽  
Polarized Luminescence

In the present work, we report the strategy for aligned packaging of in-situ grown CsPbBr3 nanorods (NR) within polystyrene (PS) nanofibers (CsPbBr3 NR@PS) based on magnetic field assisted electrospinning for...

A magnetic field in situ measurement method of the heating film in atomic sen

2021 ◽  
pp. 1-1
Author(s):  
Xiaoyang Liang ◽  
Xinxiu Zhou ◽  
Die Hu ◽  
Wenfeng Wu ◽  
Yuchen Jia
Keyword(s):  
Magnetic Field ◽  
Measurement Method ◽  
In Situ Measurement

scholarly journals Titan's exosphere and its interaction with Saturn's magnetosphere

2008 ◽  
Vol 367 (1889) ◽  
pp. 743-752 ◽  
Author(s):  
Iannis Dandouras ◽  
Philippe Garnier ◽  
Donald G Mitchell ◽  
Edmond C Roelof ◽  
Pontus C Brandt ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Remote Sensing ◽  
Charge Exchange ◽  
Mass Spectrometer ◽  
Upper Atmosphere ◽  
Neutral Atoms ◽  
Energetic Ions ◽  
Imaging Instrument ◽  
Singly Charged

Titan's nitrogen-rich atmosphere is directly bombarded by energetic ions, due to its lack of a significant intrinsic magnetic field. Singly charged energetic ions from Saturn's magnetosphere undergo charge-exchange collisions with neutral atoms in Titan's upper atmosphere, or exosphere, being transformed into energetic neutral atoms (ENAs). The ion and neutral camera, one of the three sensors that comprise the magnetosphere imaging instrument (MIMI) on the Cassini/Huygens mission to Saturn and Titan, images these ENAs like photons, and measures their fluxes and energies. These remote-sensing measurements, combined with the in situ measurements performed in the upper thermosphere and in the exosphere by the ion and neutral mass spectrometer instrument, provide a powerful diagnostic of Titan's exosphere and its interaction with the Kronian magnetosphere. These observations are analysed and some of the exospheric features they reveal are modelled.

scholarly journals On the Fluctuation Induced Excess Conductivity in Stainless Steel Sheathed MgB2 Tapes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Suchitra Rajput ◽  
Sujeet Chaudhary
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Stainless Steel ◽  
Coherence Length ◽  
Three Dimensional ◽  
Excess Conductivity ◽  
Scaling Functions ◽  
Critical Fluctuations ◽  
Scaling Models

We report on the analyses of fluctuation induced excess conductivity in the - behavior in the in situ prepared MgB2 tapes. The scaling functions for critical fluctuations are employed to investigate the excess conductivity of these tapes around transition. Two scaling models for excess conductivity in the absence of magnetic field, namely, first, Aslamazov and Larkin model, second, Lawrence and Doniach model, have been employed for the study. Fitting the experimental - data with these models indicates the three-dimensional nature of conduction of the carriers as opposed to the 2D character exhibited by the HTSCs. The estimated amplitude of coherence length from the fitted model is ~21 Å.

Desorption of hydrogen from an electrode surface under influence of an external magnetic field – In-situ microscopic observations

2009 ◽  
Vol 11 (2) ◽  
pp. 425-429 ◽  
Author(s):  
Jakub Adam Koza ◽  
Sascha Mühlenhoff ◽  
Margitta Uhlemann ◽  
Kerstin Eckert ◽  
Annett Gebert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electrode Surface

Global coronal and heliospheric magnetic field modelling for Solar Orbiter

2021 ◽  
Author(s):  
Thomas Wiegelmann ◽  
Thomas Neukirch ◽  
Iulia Chifu ◽  
Bernd Inhester
Keyword(s):  
Magnetic Field ◽  
Solar Rotation ◽  
Coronal Magnetic Field ◽  
Important Research ◽  
Parker Spiral ◽  
Important Research Topic ◽  
Mhd Equilibria ◽  
Solar Wind Flow ◽  
Nonlinear Force

&lt;p&gt;Computing the solar coronal magnetic field and plasma&lt;br&gt;environment is an important research topic on it's own right&lt;br&gt;and also important for space missions like Solar Orbiter to&lt;br&gt;guide the analysis of remote sensing and in-situ instruments.&lt;br&gt;In the inner solar corona plasma forces can be neglected and&lt;br&gt;the field is modelled under the assumption of a vanishing&lt;br&gt;Lorentz-force. Further outwards (above about two solar radii)&lt;br&gt;plasma forces and the solar wind flow has to be considered.&lt;br&gt;Finally in the heliosphere one has to consider that the Sun&lt;br&gt;is rotating and the well known Parker-spiral forms.&lt;br&gt;We have developed codes based on optimization principles&lt;br&gt;to solve nonlinear force-free, magneto-hydro-static and&lt;br&gt;stationary MHD-equilibria. In the present work we want to&lt;br&gt;extend these methods by taking the solar rotation into account.&lt;/p&gt;

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