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.

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.

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

scholarly journals Characterizing the γ-ray long-term variability of PKS 2155−304 with H.E.S.S. and Fermi-LAT

2017 ◽  
Vol 598 ◽  
pp. A39 ◽  
Author(s):  
◽  
H. Abdalla ◽  
A. Abramowski ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  
Keyword(s):  
Flicker Noise ◽  
High Energy ◽  
Long Term Results ◽  
Noise Power ◽  
Quiescent State ◽  
Physical Processes ◽  
Bl Lac Objects ◽  
Power Spectral ◽  
Bl Lac

Studying the temporal variability of BL Lac objects at the highest energies provides unique insights into the extreme physical processes occurring in relativistic jets and in the vicinity of super-massive black holes. To this end, the long-term variability of the BL Lac object PKS 2155−304 is analyzed in the high (HE, 100 MeV < E < 300 GeV) and very high energy (VHE, E > 200 GeV) γ-ray domain. Over the course of ~9 yr of H.E.S.S. observations the VHE light curve in the quiescent state is consistent with a log-normal behavior. The VHE variability in this state is well described by flicker noise (power-spectral-density index βVHE = 1.10+0.10-0.13) on timescales larger than one day. An analysis of ~5.5 yr of HE Fermi-LAT data gives consistent results (βHE = 1.20+0.21-0.23, on timescales larger than 10 days) compatible with the VHE findings. The HE and VHE power spectral densities show a scale invariance across the probed time ranges. A direct linear correlation between the VHE and HE fluxes could neither be excluded nor firmly established. These long-term-variability properties are discussed and compared to the red noise behavior (β ~ 2) seen on shorter timescales during VHE-flaring states. The difference in power spectral noise behavior at VHE energies during quiescent and flaring states provides evidence that these states are influenced by different physical processes, while the compatibility of the HE and VHE long-term results is suggestive of a common physical link as it might be introduced by an underlying jet-disk connection.

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

&lt;p&gt;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&lt;sub&gt;LL&lt;/sub&gt;) 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&lt;sub&gt;LL&lt;/sub&gt; have been shown to be highly event-specific. In the frame of SafeSpace project we have used 12 years (2009 &amp;#8211; 2020) of multi-point magnetic and electric field measurements from THEMIS A, D and E satellites to create a database of calculated D&lt;sub&gt;LL&lt;/sub&gt;. In this work we present the first statistics on the evolution of D&lt;sub&gt;LL &lt;/sub&gt;during the various phases of Solar cycle 24 with respect to the various solar wind parameters and geomagnetic indices.&lt;/p&gt;&lt;p&gt;This work has received funding from the European Union's Horizon 2020 research and innovation programme &amp;#8220;SafeSpace&amp;#8221; under grant agreement No 870437.&lt;/p&gt;

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

&lt;p&gt;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.&lt;/p&gt;

scholarly journals Nonmedical Interventions for Schizophrenia: A Review of Diet, Exercise and Social Roles

2020 ◽  
Author(s):  
Daniel S. Helman
Keyword(s):  
Term Treatment ◽  
Physical Processes ◽  
Dietary Interventions ◽  
Short Term ◽  
Alternative Interventions ◽  
Social Interventions ◽  
General Utility ◽  
Long Term Treatment ◽  
Abnormal Lipid Metabolism

Schizophrenia is a major mental illness with a disease course that is influenced by lifestyle. The risk-benefit ratio for alternative interventions is more favorable than for antipsychotics in long-term treatment. Dietary interventions may target autoimmune features, vitamin or mineral deficiencies, abnormal lipid metabolism, gluten sensitivity or others. Examples of interventions involving diet, physical activity or physical processes, or social interventions including talk therapy exist in the literature. Notwithstanding, the general utility of these types of interventions remains inconclusive, awaiting long-term randomized trials. A perspective that separates the cause of the disease from its symptoms may be helpful in treatment planning and is warranted to distinguish between short-term and long-term recovery goals.

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.

Simulations of the Relativistic Radiation Belt Electrons Using the VERB-3D Code

2021 ◽  
Author(s):  
Dedong Wang ◽  
Yuri Shprits ◽  
Alexander Drozdov ◽  
Nikita Aseev ◽  
Irina Zhelavskaya ◽  
...  
Keyword(s):  
Space Weather ◽  
Radiation Belt ◽  
Model Performance ◽  
Dynamic Evolution ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Van Allen Probes ◽  
Radiation Belt Electrons ◽  
Simulation Results

&lt;p&gt;Using the three-dimensional Versatile Electron Radiation Belt (VERB-3D) code, we perform simulations to investigate the dynamic evolution of relativistic electrons in the Earth&amp;#8217;s outer radiation belt. In our simulations, we use data from the Geostationary Operational Environmental Satellites (GOES) to set up the outer boundary condition, which is the only data input for simulations. The magnetopause shadowing effect is included by using last closed drift shell (LCDS), and it is shown to significantly contribute to the dropouts of relativistic electrons at high $L^*$. We validate our simulation results against measurements from Van Allen Probes. In long-term simulations, we test how the latitudinal dependence of chorus waves can affect the dynamics of the radiation belt electrons. Results show that the variability of chorus waves at high latitudes is critical for modeling of megaelectron volt (MeV) electrons. We show that, depending on the latitudinal distribution of chorus waves under different geomagnetic conditions, they cannot only produce a net acceleration but also a net loss of MeV electrons. Decrease in high&amp;#8208;latitude chorus waves can tip the balance between acceleration and loss toward acceleration, or alternatively, the increase in high&amp;#8208;latitude waves can result in a net loss of MeV electrons. Variations in high&amp;#8208;latitude chorus may account for some of the variability of MeV electrons.&amp;#160;&lt;/p&gt;&lt;p&gt;Our simulation results for the NSF GEM Challenge Events show that the position of the plasmapause plays a significant role in the dynamic evolution of relativistic electrons. We also perform simulations for the COSPAR International Space Weather Action Team (ISWAT) Challenge for the year 2017. The COSPAR ISWAT is a global hub for collaborations addressing challenges across the field of space weather. One of the objectives of the G3-04 team &amp;#8220;Internal Charging Effects and the Relevant Space Environment&amp;#8221; is model performance assessment and improvement. One of the expected outputs is a more systematic assessment of model performance under different conditions. The G3-04 team proposed performing benchmarking challenge runs. We &amp;#8216;fly&amp;#8217; a virtual satellite through our simulation results and compare the simulated differential electron fluxes at 0.9 MeV and 57.27 degrees local pitch-angle with the fluxes measured by the Van Allen Probes. In general, our simulation results show good agreement with observations. We calculated several different matrices to validate our simulation results against satellite observations.&lt;/p&gt;

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