Long‐Term Dropout of Relativistic Electrons in the Outer Radiation Belt During Two Sequential Geomagnetic Storms

2020 ◽  
Vol 125 (10) ◽  
Author(s):  
H. Wu ◽  
T. Chen ◽  
V. V. Kalegaev ◽  
M. I. Panasyuk ◽  
N. A. Vlasova ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Relativistic Electrons ◽  
Outer Radiation Belt

On the effect of ULF waves on the outer radiation belt during geomagnetic storms

2021 ◽  
Author(s):  
Christopher Lara ◽  
Pablo S. Moya ◽  
Victor Pinto ◽  
Javier Silva ◽  
Beatriz Zenteno
Keyword(s):  
Relativistic Electron ◽  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Cumulative Effect ◽  
Radiation Belts ◽  
Ulf Waves ◽  
Relativistic Electrons ◽  
Relative Role ◽  
Outer Radiation Belt ◽  
Ulf Wave

<p>The inner magnetosphere is a very important region to study, as with satellite-based communications increasing day after day, possible disruptions are especially relevant due to the possible consequences in our daily life. It is becoming very important to know how the radiation belts behave, especially during strong geomagnetic activity. The radiation belts response to geomagnetic storms and solar wind conditions is still not fully understood, as relativistic electron fluxes in the outer radiation belt can be depleted, enhanced or not affected following intense activity. Different studies show how these results vary in the face of different events. As one of the main mechanisms affecting the dynamics of the radiation belt are wave-particle interactions between relativistic electrons and ULF waves. In this work we perform a statistical study of the relationship between ULF wave power and relativistic electron fluxes in the outer radiation belt during several geomagnetic storms, by using magnetic field and particle fluxes data measured by the Van Allen Probes between 2012 and 2017. We evaluate the correlation between the changes in flux and the cumulative effect of ULF wave activity during the main and recovery phases of the storms for different position in the outer radiation belt and energy channels. Our results show that there is a good correlation between the presence of ULF waves and the changes in flux during the recovery phase of the storm and that correlations vary as a function of energy. Also, we can see in detail how the ULF power change for the electron flux at different L-shell We expect these results to be relevant for the understanding of the relative role of ULF waves in the enhancements and depletions of energetic electrons in the radiation belts for condition described.</p>

scholarly journals On the Effect of Geomagnetic Storms on Relativistic Electrons in the Outer Radiation Belt: Van Allen Probes Observations

2017 ◽  
Vol 122 (11) ◽  
pp. 11,100-11,108 ◽  
Author(s):  
Pablo S. Moya ◽  
Víctor A. Pinto ◽  
David G. Sibeck ◽  
Shrikanth G. Kanekal ◽  
Daniel N. Baker
Keyword(s):  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Van Allen Probes

scholarly journals A Framework for Understanding and Quantifying the Loss and Acceleration of Relativistic Electrons in the Outer Radiation Belt During Geomagnetic Storms

Space Weather ◽  
2020 ◽  
Vol 18 (5) ◽  
Author(s):  
Kyle R. Murphy ◽  
Ian R. Mann ◽  
David G. Sibeck ◽  
I. Jonathan Rae ◽  
C.E.J. Watt ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Relativistic Electrons ◽  
Outer Radiation Belt

scholarly journals Relativistic electrons of the outer radiation belt and methods of their forecast (review)

2017 ◽  
Vol 3 (1) ◽  
pp. 57-72 ◽  
Author(s):  
Александр Потапов ◽  
Alexander Potapov
Keyword(s):  
Lead Time ◽  
Radiation Belt ◽  
High Energy ◽  
Relativistic Electrons ◽  
Physical Processes ◽  
Weather Factors ◽  
Outer Radiation Belt ◽  
Magneto Sphere ◽  
Satellite Equipment

The paper reviews studies of the dynamics of relativistic electrons in the geosynchronous region. It lists the physical processes that lead to the acceleration of electrons filling the outer radiation belt. As one of the space weather factors, high-energy electron fluxes pose a serious threat to the operation of satellite equipment in one of the most populated orbital regions. Necessity is emphasized for efforts to develop methods of forecasting the situation in this part of the magneto-sphere, possible predictors are listed, and their classifi-cation is given. An example of a predictive model for forecasting relativistic electron flux with a lead time of 1–2 days is proposed. Some questions of practical or-ganization of prediction are discussed; the main objec-tives of short-term, medium-term, and long-term fore-casts are listed.

scholarly journals Relativistic electrons of the outer radiation belt and methods of their forecast (review)

2017 ◽  
Vol 3 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Александр Потапов ◽  
Alexander Potapov
Keyword(s):  
Lead Time ◽  
Radiation Belt ◽  
High Energy ◽  
Relativistic Electrons ◽  
Physical Processes ◽  
Short Term ◽  
Weather Factors ◽  
Outer Radiation Belt ◽  
Satellite Equipment

The paper reviews studies of the dynamics of relativistic electrons in the geosynchronous region. It lists the physical processes that lead to the acceleration of electrons filling the outer radiation belt. As one of the space weather factors, high-energy electron fluxes pose a serious threat to the operation of satellite equipment in one of the most populated orbital regions. Necessity is emphasized for efforts to develop methods of forecasting the situation in this part of the magnetosphere, possible predictors are listed, and their classification is given. An example of a predictive model for forecasting relativistic electron flux with a lead time of 1–2 days is proposed. Some questions of practical organization of prediction are discussed; the main objectives of short-term, medium-term, and long-term forecasts are listed.

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 PreMevE Update: Forecasting Ultra‐relativistic Electrons inside Earth’s Outer Radiation Belt

Space Weather ◽  
2021 ◽  
Author(s):  
Saurabh Sinha ◽  
Yue Chen ◽  
Youzuo Lin ◽  
Rafael Pires de Lima
Keyword(s):  
Radiation Belt ◽  
Relativistic Electrons ◽  
Outer Radiation Belt

PROBLEMS OF THE OUTER RADIATION BELT FORMATION AND TOPOLOGICAL FEATURES OF HIGH LATITUDE MAGNETOSPHERE

2021 ◽  
Vol 44 ◽  
pp. 7-11
Author(s):  
Elena Antonova ◽  
Keyword(s):  
Geomagnetic Storm ◽  
High Latitude ◽  
Radiation Belt ◽  
Ring Current ◽  
Outer Part ◽  
Auroral Oval ◽  
Plasma Pressure ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Topological Features

We analyzed the problems of formation of the outer radiation belt (ORB) taking into consideration the latest changes in our understanding of the high-latitude magnetospheric topology. This includes strong evidence that the auroral oval maps to the outer part of the ring current, meanwhile the ORB polar boundary maps inside the auroral oval. Our analysis also includes the variation of the plasma pressure distribution and the time of the acceleration of relativistic electrons during geomagnetic storm. It is shown that the maximum of ORB is formed after the geomagnetic storm in the region of plasma pressure maximum. The position of this maximum agrees with the prediction of the ORB formation theory based on the analysis of ring current development during storm. We emphasize the role of adiabatic processes in the ORB dynamics and the importance of the substorm injections during storm recovery phase for the formation of enhanced fluxes of ORB electrons after the storm.

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