Three-dimensional stochastic modeling of radiation belts in adiabatic invariant coordinates

A 3-D model for solving the radiation belt diffusion equation in adiabatic invariant coordinates has been developed and tested. The model, named REM (for Radbelt Electron Model), obtains a probabilistic solution by solving a set of Itô stochastic differential equations that are mathematically equivalent to the diffusion equation. This method is capable of solving diffusion equations with a full 3-D diffusion tensor, including the radial-local cross diffusion components. The correct form of the boundary condition at equatorial pitch-angle α0 = 90° is also derived. The model is applied to a simulation of the October 2002 storm event. At α0 near 90°, our results are quantitatively consistent with GPS observations of phase-space density (PSD) increases, suggesting dominance of radial diffusion; at smaller α0, the observed PSD increases are overestimated by the model, possibly due to the α0-independent radial diffusion coefficients, or to insufficientelectron loss in the model, or both. Statistical analysis of the stochastic processes provides further insights into the diffusion processes, showing distinctive electron source distributions with and without local acceleration

Simulation of high-energy radiation belt electron fluxes using NARMAX-VERB coupled codes

This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code, to simulate energetic electron fluxes in the outer radiation belt environment. The coupled system has been tested for three extended time periods totalling several weeks of observations. The time periods involved periods of quiet, moderate, and strong geomagnetic activity and captured a range of dynamics typical of the radiation belts. The model has successfully simulated energetic electron fluxes for various magnetospheric conditions. Physical mechanisms that may be responsible for the discrepancies between the model results and observations are discussed

Transport of the plasma sheet electrons to the geostationary distances

The transport and acceleration of low‐energy electrons (50–250 keV) from the plasma sheet to the geostationary orbit were investigated. Two moderate storm events, which occurred on 6–7 November 1997 and 12–14 June 2005, were modeled using the Inner Magnetosphere Particle Transport and Acceleration model (IMPTAM) with the boundary set at 10  R E in the plasma sheet. The output of the IMPTAM was compared to the observed electron fluxes in four energy ranges (50–225 keV) measured by the Synchronous Orbit Particle Analyzer instrument onboard the Los Alamos National Laboratory spacecraft. It was found that the large‐scale convection in combination with substorm‐associated impulsive fields is the drivers of the transport of plasma sheet electrons from 10  R E to geostationary orbit at 6.6  R E during storm times. The addition of radial diffusion had no significant influence on the modeled electron fluxes. At the same time, the modeled electron fluxes are one (two) order(s) smaller than the observed ones for 50–150 keV (150–225 keV) electrons, respectively, most likely due to inaccuracy of electron boundary conditions. The loss processes due to wave‐particle interactions were not considered. The choice of the large‐scale convection electric field model used in simulations did not have a significant influence on the modeled electron fluxes, since there is not much difference between the equipotential contours given by the Volland‐Stern and the Boyle et al . (1997) models at distances from 10 to 6.6  R E in the plasma sheet. Using the TS05 model for the background magnetic field instead of the T96 model resulted in larger deviations of the modeled electron fluxes from the observed ones due to specific features of the TS05 model. The increase in the modeled electron fluxes can be as large as two orders of magnitude when substorm‐associated electromagnetic fields were taken into account. The obtained model distribution of low‐energy electron fluxes can be used as an input to the radiation belt models. This seed population for radiation belts will affect the local acceleration up to relativistic energies. Key Points Transport of plasma sheet electrons due to convection and substorms Importance of boundary conditions in plasma sheet Importance of magnetic field model choicePeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97187/1/jgra50047.pd

The quasi-electrostatic mode of chorus waves and electron nonlinear acceleration

International audienceSelected Time History of Events and Macroscale Interactions During Substorms observationsat medium latitudes of highly oblique and high-amplitude chorus waves are presented and analyzed. Thepresence of such very intense waves is expected to have important consequences on electron energizationin the magnetosphere. An analytical model is therefore developed to evaluate the efficiency of the trappingand acceleration of energetic electrons via Landau resonance with such nearly electrostatic chorus waves.Test-particle simulations are then performed to illustrate the conclusions derived from the analytical model,using parameter values consistent with observations. It is shown that the energy gain can be much largerthan the initial particle energy for 10 keV electrons, and it is further demonstrated that this energy gain isweakly dependent on the density variation along field lines

Global model of plasmaspheric hiss from multiple satellite observations

We present a global model of plasmaspheric hiss, using data from eight satellites, extending the coverage and improving the statistics of existing models. We use geomagnetic activity dependent templates to separate plasmaspheric hiss from chorus. In the region 22–14 magnetic local time (MLT) the boundary between plasmaspheric hiss and chorus moves to lower values with increasing geomagnetic activity. The average wave intensity of plasmaspheric hiss is largest on the dayside and increases with increasing geomagnetic activity from midnight through dawn to dusk. Plasmaspheric hiss is most intense and spatially extended in the 200 to 500 Hz frequency band during active conditions, 400 750 nT, with an average intensity of 1,128 pT in the region 05–17 MLT from 1.5 . In the prenoon sector, waves in the 100 to 200 Hz frequency band peak near the magnetic equator and decrease in intensity with increasing magnetic latitude, inconsistent with a source from chorus outside the plasmapause, but more consistent with local amplification by substorm‐injected electrons. At higher frequencies the average wave intensities in this sector exhibit two peaks, one near the magnetic equator and one at high latitudes, 45° °, with a minimum at intermediate latitudes, 30° °, consistent with a source from chorus outside the plasmapause. In the premidnight sector, the intensity of plasmaspheric hiss in the frequency range 50 < f < 1,000 Hz decreases with increasing geomagnetic activity. The source of this weak premidnight plasmaspheric hiss is likely to be chorus at larger in the postnoon sector that enters that plasmasphere in the postnoon sector and subsequently propagates eastward in MLT

Introduction to special section on “Results of the National Science Foundation Geospace Environment Modeling Inner Magnetosphere/Storms Assessment Challenge”

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95288/1/jgra18577.pd

Entropy mapping of the outer electron radiation belt between the magnetotail and geosynchronous orbit

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94614/1/jgra21264.pd

Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt

Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave–particle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion cyclotron waves. However, this has failed to accurately reproduce the third belt. Using a data driven, time-dependent specification of ultra-low-frequency (ULF) waves we show for the first time how the third radiation belt is established as a simple, elegant consequence of storm-time extremely fast outward ULF wave transport. High-frequency wave–particle scattering loss into the atmosphere is not needed in this case. When rapid ULF wave transport coupled to a dynamic boundary is accurately specified, the sensitive dynamics controlling the enigmatic ultra-relativistic third radiation belt are naturally explaine

Το κοβάλτιο στη παραγωγή μπαταριών των ηλεκτρικών οχημάτων

Το παγκόσμιο ενδιαφέρον για τον κρίσιμο ρόλο του κοβαλτίου στην αλυσίδα εφοδιασμού ηλεκτρικών οχημάτων, εμφαίνεται από τη πρόσφατη διεξαγωγή του συνεδρίου Cobalt Institute 2021 που υλοποιήθηκε 18-19 Μαΐου 2021 με έμφαση στο ρόλο του κοβαλτίου σε ένα βιώσιμο μέλλον, την κατάσταση της αγοράς τους τελευταίους 12 μήνες. Οι εξελίξεις στις μπαταρίες ιόντων Λιθίου και κυψελών Κοβαλτίου καθώς και σχετικά θέματα από την εξόρυξη πρώτων υλών, τη χημική επεξεργασία, την παραγωγή κυψελών και την ανακύκλωση ήταν βασικό θέμα στο Cobalt Special της Benchmark που διεξήχθη την Τετάρτη 19 Μαΐου, 2021 σε συνεργασία με το συνέδριο του Cobalt Institute. Απώτερος σκοπός κατά την μελέτη και συγγραφή της Εργασίας αυτής κύριο μέλημα αποτέλεσε η καταγραφή των σύγχρονων τάσεων και εξελίξεων στον κύκλο χρήσης του κοβαλτίου στους ηλεκτρικούς συσσωρευτές για την παραγωγή ηλεκτρικών οχημάτων. Αφορά σε ένα τεράστιο σύγχρονο πρόβλημα με γεωλογικές, ενεργειακές, περιβαλλοντολογικές, οικονομικές αλλά και κοινωνικές διαστάσεις. Στα τρία πρώτα Κεφάλαια γίνεται λόγος για τον ρόλο του κοβαλτίου ως κρίσιμη πρώτη ύλη - όπως και των υπόλοιπων υλών μπαταρίας- τα μοναδικά χαρακτηριστικά του ως μέταλλο, τις ενώσεις που σχηματίζει και τις συγκεντρώσεις του στην γη και υποθαλάσσια που συνιστούν ή θα αποτελέσουν οικονομικές αποθέσεις κοιτασμάτων παγκοσμίως και ιδιαιτέρως στην Ευρώπη. Γίνεται ιδιαίτερη αναφορά στις μεθόδους επεξεργασίας, ανάκτησης του κοβαλτίου όπως και τα επίπεδα παραγωγής του μετάλλου προς αξιοποίηση. Τα υπόλοιπα τρία Κεφάλαια επικεντρώνονται στις παρούσες και μελλοντικά αρκετά υποσχόμενες εφαρμογές που συμμετέχει το κοβάλτιο εκτός της ηλεκτροκίνησης, στις σύγχρονες τάσεις ανακύκλωσης, της αλυσίδας εφοδιασμού των συσσωρευτών των ηλεκτρικών οχημάτων και των εξελίξεων του εμπορίου συσσωρευτών σε διεθνή κλίμακα .The global interest in the crucial role of cobalt in the supply chain of electric vehicles is evident from the recent Cobalt Institute 2021 conference held on 18-19 May 2021 with an emphasis on the role of cobalt in a sustainable future, the market situation of the latter 12 months. Developments in Lithium-ion Batteries and Cobalt Cells as well as related topics from raw material extraction, chemical processing, cell production and recycling were a key topic at Benchmark&apos;s Cobalt Special held on Wednesday, May 19, 2021 in collaboration with the conference of the Cobalt Institute. The ultimate goal in the study and writing of this Thesis, the main concern was to record current trends and developments in the cycle of use of cobalt in electric batteries for the production of electric vehicles. It concerns a huge modern problem with geological, energy, environmental, economic and social dimensions. The first three Chapters discuss the role of cobalt as a critical raw material - like other battery materials - its unique characteristics as a metal, the compounds it forms, and its concentrations on land and submarines which constitute, or will constitute economic mineral deposits worldwide and especially in Europe. Special reference is made to the methods of processing, recovery of cobalt, as well as the production levels of the metal to be exploited. The other three Chapters focus on the current and future promising applications of cobalt, in addition to electric propulsion, modern recycling trends, the supply chain of electric vehicle batteries and the development of the battery industry internationally