scholarly journals The "SafeSpace" Radial Diffusion Coefficients Database: Dependencies and application to simulations

2021 ◽  
Author(s):  
Christos Katsavrias ◽  
Afroditi Nasi ◽  
Ioannis A. Daglis ◽  
Sigiava Aminalragia-Giamini ◽  
Nourallah Dahmen ◽  
...  
Keyword(s):  
Solar Wind ◽  
Diffusion Coefficients ◽  
Low Frequency ◽  
Field Measurements ◽  
Radial Diffusion ◽  
Wind Pressure ◽  
Relativistic Electrons ◽  
Interplanetary Coronal Mass Ejections ◽  
Outer Radiation Belt ◽  
Semi Empirical

Abstract. Radial diffusion has been established as one of the most important mechanisms contributing to both the acceleration and loss of relativistic electrons in the outer radiation belt. In the framework of the SafeSpace project we have used 9 years (2011–2019) of multi-point magnetic and electric field measurements from THEMIS A, D and E satellites to create a database of accurately calculated radial diffusion coefficients (DLL) spanning an L* range from 3 to 8. In this work we investigate the dependence of the DLL on the various solar wind parameters, geomagnetic indices and coupling functions, and moreover, on the spatial parameters L* and Magnetic Local Time (MLT), during the solar cycle 24. The spatial distribution of the DLL reveals important MLT dependence rising from the various Ultra Low Frequency (ULF) wave generation mechanisms. Furthermore, we investigate via a superposed analysis, the dependence of the DLL on solar wind drivers. We show that the Interplanetary Coronal Mass Ejections (ICME) driven disturbances accompanied by high solar wind pressure values combined with intense magnetospheric compression produce DLLB  values comparable or even greater than the ones of DLLE. This feature cannot be captured by semi-empirical models and introduces a significant energy dependence on the DLL. Finally, we show the advantages of the use of accurately calculated DLL by means of numerical simulations of relativistic electron fluxes performed with the Salammbô code and significant deviations of several semi-empirical model predictions depending on the level of geomagnetic activity and L-shell.

Radial diffusion coefficients database in the frame of SafeSpace project

2021 ◽  
Author(s):  
Christos Katsavrias ◽  
Ioannis A. Daglis ◽  
Afroditi Nasi ◽  
Constantinos Papadimitriou ◽  
Marina Georgiou
Keyword(s):  
Diffusion Coefficients ◽  
Radiation Belt ◽  
Field Measurements ◽  
Radial Diffusion ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Horizon 2020 ◽  
Research And Innovation ◽  
The Difference ◽  
Cycle 24

<p>Radial diffusion has been established as one of the most important mechanisms contributing the acceleration and loss of relativistic electrons in the outer radiation belt. Over the past few years efforts have been devoted to provide empirical relationships of radial diffusion coefficients (D<sub>LL</sub>) for radiation belt simulations yet several studies have suggested that the difference between the various models can be orders of magnitude different at high levels of geomagnetic activity as the observed D<sub>LL</sub> have been shown to be highly event-specific. In the frame of SafeSpace project we have used 12 years (2009 – 2020) of multi-point magnetic and electric field measurements from THEMIS A, D and E satellites to create a database of calculated D<sub>LL</sub>. In this work we present the first statistics on the evolution of D<sub>LL </sub>during the various phases of Solar cycle 24 with respect to the various solar wind parameters and geomagnetic indices.</p><p>This work has received funding from the European Union's Horizon 2020 research and innovation programme “SafeSpace” under grant agreement No 870437.</p>

ULF Wave Power During Geomagnetic Storms and Implications for Radial Diffusion Processes

2021 ◽  
Author(s):  
Jasmine Sandhu ◽  
Jonathan Rae ◽  
John Wygant ◽  
Aaron Breneman ◽  
Sheng Tian ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Diffusion Coefficients ◽  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Radial Diffusion ◽  
Ulf Waves ◽  
Wave Power ◽  
Outer Radiation Belt ◽  
Large Variability ◽  
Ulf Wave

<p>Ultra Low Frequency (ULF) waves drive radial diffusion of radiation belt electrons, where this process contributes to and, at times, dominates energisation, loss, and large scale transport of the outer radiation belt. In this study we quantify the changes and variability in ULF wave power during geomagnetic storms, through a statistical analysis of Van Allen Probes data for the time period spanning 2012 – 2019. The results show that global wave power enhancements occur during the main phase, and continue into the recovery phase of storms. Local time asymmetries show sources of ULF wave power are both external solar wind driving as well as internal sources from coupling with ring current ions and substorms.</p><p>The statistical analysis demonstrates that storm time ULF waves are able to access lower L values compared to pre-storm conditions, with enhancements observed within L = 4. We assess how magnetospheric compressions and cold plasma distributions shape how ULF wave power propagates through the magnetosphere. Results show that the Earthward displacement of the magnetopause is a key factor in the low L enhancements. Furthermore, the presence of plasmaspheric plumes during geomagnetic storms plays a crucial role in trapping ULF wave power, and contributes significantly to large storm time enhancements in ULF wave power.</p><p>The results have clear implications for enhanced radial diffusion of the outer radiation belt during geomagnetic storms. Estimates of storm time radial diffusion coefficients are derived from the ULF wave power observations, and compared to existing empirical models of radial diffusion coefficients. We show that current Kp-parameterised models, such as the Ozeke et al. [2014] model, do not fully capture the large variability in storm time radial diffusion coefficients or the extent of enhancements in the magnetic field diffusion coefficients.</p>

scholarly journals The RPW Low Frequency Receiver (LFR) on Solar Orbiter: in-situ LF electric and magnetic field measurements of the solar wind expansion

2020 ◽  
Author(s):  
Thomas Chust ◽  
Olivier Le Contel ◽  
Matthieu Berthomier ◽  
Alessandro Retinò ◽  
Fouad Sahraoui ◽  
...  
Keyword(s):  
Solar Wind ◽  
Low Frequency ◽  
Field Measurements ◽  
Solar Wind Plasma ◽  
Wind Condition ◽  
The Sun ◽  
Nasa Mission ◽  
Magnetic Field Measurements ◽  
Electric And Magnetic Field

<p>Solar Orbiter (SO) is an ESA/NASA mission for exploring the Sun-Heliosphere connection which has been launched in February 2020. The Low Frequency Receiver (LFR) is one of the main subsystems of the Radio and Plasma Wave (RPW) experiment on SO. It is designed for characterizing the low frequency (~0.1Hz–10kHz) electromagnetic fields & waves which develop, propagate, interact, and dissipate in the solar wind plasma. In correlation with particle observations it will help to understand the heating and acceleration processes at work during its expansion. We will present the first LFR data gathered during the Near Earth Commissioning Phase, and will compare them with MMS data recorded in similar solar wind condition.</p>

Generation of magnetic and particle Pc5 pulsations during the recovery phase of strong magnetic storms

2010 ◽  
Vol 466 (2123) ◽  
pp. 3363-3390 ◽  
Author(s):  
V. Pilipenko ◽  
O. Kozyreva ◽  
V. Belakhovsky ◽  
M. J. Engebretson ◽  
S. Samsonov
Keyword(s):  
Solar Wind ◽  
Spatial Structure ◽  
Stable State ◽  
Low Frequency ◽  
Solar Wind Plasma ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Relativistic Electrons ◽  
Oscillatory Systems ◽  
Using Data

The dynamics of intense ultra-low-frequency (ULF) activity during three successive strong magnetic storms during 29–31 October 2003 are considered in detail. The spatial structure of Pc5 waves during the recovery phases of these storms is considered not only from the perspective of possible physical mechanisms, but as an important parameter of the ULF driver of relativistic electrons. The global structure of these disturbances is studied using data from a worldwide array of magnetometers and riometers augmented with data from particle detectors and magnetometers on board magnetospheric satellites (GOES, LANL). The local spatial structure is examined using the IMAGE magnetometers and Finnish riometer array. Though a general similarity between the quasi-periodic magnetic and riometer variations is observed, their local propagation patterns turn out to be different. To interpret the observations, we suggest a hypothesis of coupling between two oscillatory systems—a magnetospheric magnetohydrodynamic (MHD) waveguide/resonator and a system consisting of turbulence + electrons. We propose that the observed Pc5 oscillations are the result of MHD waveguide excitation along the dawn and dusk flanks of the magnetosphere. The magnetospheric waveguide turns out to be in a meta-stable state under high solar wind velocities, and quasi-periodic fluctuations of the solar wind plasma density stimulate the waveguide excitation.

scholarly journals Association of radiation belt electron enhancements with earthward penetration of Pc5 ULF waves: a case study of intense 2001 magnetic storms

2015 ◽  
Vol 33 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
M. Georgiou ◽  
I. A. Daglis ◽  
E. Zesta ◽  
G. Balasis ◽  
I. R. Mann ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Recovery Phase ◽  
Wave Activity ◽  
Magnetic Storms ◽  
Ulf Waves ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Magnetometer Arrays ◽  
The One

Abstract. Geospace magnetic storms, driven by the solar wind, are associated with increases or decreases in the fluxes of relativistic electrons in the outer radiation belt. We examine the response of relativistic electrons to four intense magnetic storms, during which the minimum of the Dst index ranged from −105 to −387 nT, and compare these with concurrent observations of ultra-low-frequency (ULF) waves from the trans-Scandinavian IMAGE magnetometer network and stations from multiple magnetometer arrays available through the worldwide SuperMAG collaboration. The latitudinal and global distribution of Pc5 wave power is examined to determine how deep into the magnetosphere these waves penetrate. We then investigate the role of Pc5 wave activity deep in the magnetosphere in enhancements of radiation belt electrons population observed in the recovery phase of the magnetic storms. We show that, during magnetic storms characterized by increased post-storm electron fluxes as compared to their pre-storm values, the earthward shift of peak and inner boundary of the outer electron radiation belt follows the Pc5 wave activity, reaching L shells as low as 3–4. In contrast, the one magnetic storm characterized by irreversible loss of electrons was related to limited Pc5 wave activity that was not intensified at low L shells. These observations demonstrate that enhanced Pc5 ULF wave activity penetrating deep into the magnetosphere during the main and recovery phase of magnetic storms can, for the cases examined, distinguish storms that resulted in increases in relativistic electron fluxes in the outer radiation belts from those that did not.

Identification of interplanetary parameter schemes which drive the variability of the magnetospheric radiation environment

2020 ◽  
Author(s):  
Christos Katsavrias ◽  
Afroditi Nasi ◽  
Constantinos Papadimitriou ◽  
Sigiava Aminalragia-Giamini ◽  
Ingmar Sandberg ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Solar Energetic Particle ◽  
Radiation Environment ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Core Technology ◽  
Cycle 24 ◽  
Solar Wind Parameters ◽  
Time And Energy

<p>The energetic particles of the outer radiation belt are highly variable in space, time and energy, due to the complex interplay between various mechanisms that contribute to their energization and/or loss. Previous studies have focused on the influence of solar wind and magnetospheric processes on the electron population dynamics, showing that the eventual effect of the various interplanetary drivers results from different combinations of IMF and solar wind parameters. Yet, all of these studies were limited in temporal, spatial and energy coverage. In this work, we take advantage of a large dataset, which includes multipoint measurements of electron fluxes covering a large energy range and various orbits (e.g. Van Allen Probes, GOES, HIMAWARI, SREM monitors, etc.), as well as approximately the whole solar cycle 24 to deduce specific interplanetary parameter schemes that drive enhancements or depletions of relativistic electrons in the outer radiation belt. Our study also investigates parameters which are correlated to the Solar Energetic Particle (SEP) environment with the long-term goal of connecting the two sets of results for coherent merging of environment models.</p><p>This work is supported by ESA’s Science Core Technology Programme (CTP) under contract No. 4000127282/19/IB/gg.</p>

scholarly journals Average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit

2008 ◽  
Vol 26 (6) ◽  
pp. 1335-1339 ◽  
Author(s):  
R. Kataoka ◽  
Y. Miyoshi
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Radiation Belt ◽  
Dynamic Pressure ◽  
Recovery Phase ◽  
Geosynchronous Orbit ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Flux Enhancement ◽  
Solar Wind Structure

Abstract. We report average profiles of the solar wind and outer radiation belt during the extreme flux enhancement of relativistic electrons at geosynchronous orbit (GEO). It is found that seven of top ten extreme events at GEO during solar cycle 23 are associated with the magnetosphere inflation during the storm recovery phase as caused by the large-scale solar wind structure of very low dynamic pressure (<1.0 nPa) during rapid speed decrease from very high (>650 km/s) to typical (400–500 km/s) in a few days. For the seven events, the solar wind parameters, geomagnetic activity indices, and relativistic electron flux and geomagnetic field at GEO are superposed at the local noon period of GOES satellites to investigate the physical cause. The average profiles support the "double inflation" mechanism that the rarefaction of the solar wind and subsequent magnetosphere inflation are one of the best conditions to produce the extreme flux enhancement at GEO because of the excellent magnetic confinement of relativistic electrons by reducing the drift loss of trapped electrons at dayside magnetopause.

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