Observation results of relativistic electrons detected by Fengyun-1 satellite and analysis of relativistic electron enhancement (REE) events

2008 ◽  
Vol 51 (12) ◽  
pp. 1947-1956 ◽  
Author(s):  
XiaoChao Yang ◽  
ShiJin Wang
Keyword(s):  
Relativistic Electron ◽  
Relativistic Electrons ◽  
Observation Results

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 Do Impulsive Solar-Energetic-Electron (SEE) Events Drive High-Voltage Charging Events on the Nightside of the Moon?

2021 ◽  
Vol 8 ◽  
Author(s):  
Joseph E. Borovsky ◽  
Gian Luca Delzanno
Keyword(s):  
Solar Wind ◽  
Relativistic Electron ◽  
Lunar Surface ◽  
Energetic Electron ◽  
Relativistic Electrons ◽  
Time Varying ◽  
The Sun ◽  
The Moon ◽  
Lunar Wake ◽  
Electrical Potentials

When the Earth’s moon is in the supersonic solar wind, the darkside of the Moon and the lunar plasma wake can be very dangerous charging environments. In the absence of photoelectron emission (dark) and in the absence of cool plasma (wake), the emission or collection of charge to reduce electrical potentials is difficult. Unique extreme charging events may occur during impulsive solar-energetic-electron (SEE) events when the lunar wake is dominated by relativistic electrons, with the potential to charge and differentially charge objects on and above the lunar surface to very-high negative electrical potentials. In this report the geometry of the magnetic connections from the Sun to the lunar nightside are explored; these magnetic connections are the pathways for SEEs from the Sun. Rudimentary charging calculations for objects in the relativistic-electron environment of the lunar wake are performed. To enable these charging calculations, secondary-electron yields for impacts by relativistic electrons are derived. Needed lunar electrical-grounding precautions for SEE events are discussed. Calls are made 1) for future dynamic simulations of the plasma wake in the presence of time-varying SEE-event relativistic electrons and time-varying solar-wind magnetic-field orientations and 2) for future charging calculations in the relativistic-electron wake environment and on the darkside lunar surface.

On the semi-annual variation of relativistic electrons in the outer radiation belt

2021 ◽  
Author(s):  
Sigiava Aminalragia-Giamini ◽  
Christos Katsavrias ◽  
Constantinos Papadimitriou ◽  
Ioannis A. Daglis ◽  
Ingmar Sandberg ◽  
...  
Keyword(s):  
Relativistic Electron ◽  
Radiation Belt ◽  
Annual Variation ◽  
European Space Agency ◽  
Phase Relationship ◽  
Radiation Environment ◽  
Relativistic Electrons ◽  
Solar Cycles ◽  
Outer Radiation Belt ◽  
Horizon 2020

<p>The nature of the semi-annual variation in the relativistic electron fluxes in the Earth’s outer radiation belt is investigated using Van Allen Probes (MagEIS and REPT) and GOES (EPS) data during solar cycle 24. We perform wavelet and cross-wavelet analysis in a broad energy and spatial range of electron fluxes and examine their phase relationship with the axial, equinoctial and Russell-McPherron mechanisms. It is found that the semi-annual variation in the relativistic electron fluxes exhibits pronounced power in the 0.3 – 4.2 MeV energy range at L-shells higher than 3.5 and, moreover, it exhibits an in-phase relationship with the Russell-McPherron effect indicating the former is primarily driven by the latter. Furthermore, the analysis of the past 3 solar cycles with GOES/EPS indicates that the semi-annual variation at geosynchronous orbit is evident during the descending phases and coincides with periods of a higher (lower) HSS (ICME) occurrence.</p><p>This work has received funding from the European Union's Horizon 2020 research and innovation programme “SafeSpace” under grant agreement No 870437 and from the European Space Agency under the “European Contribution to International Radiation Environment Near Earth (IRENE) Modelling System” activity under ESA Contract No 4000127282/19/NL/IB/gg.</p>

scholarly journals Reduced multi-scale kinetic models for the relativistic electron transport in solid targets: Effects related to secondary electrons

2010 ◽  
Vol 28 (1) ◽  
pp. 165-177 ◽  
Author(s):  
R. Duclous ◽  
J.-P. Morreeuw ◽  
V.T. Tikhonchuk ◽  
B. Dubroca
Keyword(s):  
Relativistic Electron ◽  
Energy Exchange ◽  
Plasma Temperature ◽  
Relativistic Electrons ◽  
High Current ◽  
Secondary Electrons ◽  
Electron Collisions ◽  
Relativistic Electron Beams ◽  
Multi Scale ◽  
Particle Exchange

AbstractA reduced mathematical model for the transport of high current relativistic electron beams in a dense collisional plasma is developed. Based on the hypothesis that the density of relativistic electrons is much less than the plasma density and their energy is much higher than the plasma temperature, a model with two energy scales is proposed, where the beam and plasma electrons are considered as two coupled sub-systems, which exchange the energy and particles due to collisions. The process of energy exchange is described in the Fokker-Planck approximation, where the pitch angle electron-ion and electron-electron collisions dominate. The process of particle exchange between populations, leading to the production of secondary energetic electrons, is described with a Boltzmann term. The electron-electron collisions with small impact parameters make an important contribution in the overall dynamics of the beam electrons.

scholarly journals Correlated stopping of relativistic electrons in supercompressed DT fuel

2000 ◽  
Vol 18 (2) ◽  
pp. 301-306 ◽  
Author(s):  
C. DEUTSCH ◽  
P. FROMY
Keyword(s):  
Relativistic Electron ◽  
Impact Parameter ◽  
Femtosecond Lasers ◽  
Electron Beams ◽  
Large Impact ◽  
Relativistic Electrons ◽  
Relativistic Electron Beams ◽  
Large Impact Parameter

The electromagnetic stopping of intense and relativistic electron beams (REB) arising from femtosecond lasers interacting with a precompressed deuterium–tritium (DT) fuel is investigated within the Bohr–Fermi formalism with a large impact parameter. Dynamical intrabeam correlations in the target are shown to be quantitatively significant for various arrangements of projectile electrons and the overall REB penetration in the DT fuel.

scholarly journals Identify spin property of relativistic electrons in fully relativistic laser fields

2021 ◽  
Author(s):  
Xiabing Li ◽  
Longfei Gan ◽  
Jing Wang ◽  
Jinlong Jiao ◽  
Shan Jin ◽  
...  
Keyword(s):  
Relativistic Electron ◽  
Classical Method ◽  
Mean Value ◽  
Relativistic Electrons ◽  
Single Cycle ◽  
Total Change ◽  
Theoretical Derivation ◽  
Mean Values ◽  
The Mean ◽  
Particle Interpretation

Abstract A semiclassical method is developed to study the spin evolution of a relativistic electron in an fully relativistic laser pulse. Different from the previous classical method which is based on the direct generalization of nonrelativistic spin precession equation, we perform first-principle calculations on the mean values of various spin operators with respect to a relativistic electron wavepacket. It is demonstrated, via theoretical derivation and numerical simulation, that although the Foldy-Wouthuysen operator merits the single-particle interpretation, its mean value obviously deviates from the result of the classical method, which sheds light on not only the understanding of relativistic spin itself but also broad related applications. To achieve a direct observation of such effect, a feasible experimental setup utilizing the asymmetric field of a single-cycle laser is proposed. In such geometry, the deviation is evidenced in the total change of spin which can be easily measured after the interaction.

Association of chorus waves and source/seed electrons with the enhancement of relativistic electrons in the outer Van Allen belt

2020 ◽  
Author(s):  
Afroditi Nasi ◽  
Ioannis A. Daglis ◽  
Christos Katsavrias ◽  
Wen Li
Keyword(s):  
Relativistic Electron ◽  
Radiation Belt ◽  
Geomagnetic Disturbance ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Inner Magnetosphere ◽  
Superposed Epoch Analysis ◽  
Chorus Waves ◽  
Substorm Activity ◽  
Epoch Analysis

<p>Local acceleration driven by whistler-mode chorus waves is fundamentally important for the acceleration of seed electrons in the outer radiation belt to relativistic energies. Τhis mechanism strongly depends on substorm activity and on the source electron population injected by the substorms into the inner magnetosphere. In our work we use Van Allen Probes data to investigate the features of source electrons, seed electrons and chorus waves for events of enhancement versus events of depletion of relativistic electrons in the outer Van Allen belt. To that end we calculate the electron phase space density (PSD) for five values of the first adiabatic invariant corresponding to source and seed electrons, and we perform a superposed epoch analysis of 28 geomagnetic disturbance events, out of which, 20 result in enhancement and 8 in depletion of relativistic electron PSD. Our results indicate that events resulting in significant enhancement of relativistic electron PSD in the outer radiation belt are characterized by statistically stronger and more prolonged storm and substorm activity, leading to more efficient injections of source but mostly seed electrons to the inner magnetosphere, and also to more pronounced and long-lasting chorus and Pc5 wave activity. The effect of these parameters in the acceleration of electrons seems to be determined by the abundance of seed electrons at the region of L*=4-5.</p>

scholarly journals Transport of ultraintense laser-driven relativistic electrons in dielectric targets

2020 ◽  
Vol 8 ◽  
Author(s):  
X. H. Yang ◽  
C. Ren ◽  
H. Xu ◽  
Y. Y. Ma ◽  
F. Q. Shao
Keyword(s):  
Relativistic Electron ◽  
Electric Fields ◽  
Laser Intensity ◽  
High Energy ◽  
High Energy Density ◽  
Electron Velocity ◽  
Ionization Front ◽  
Field Ionization ◽  
Relativistic Electrons ◽  
Collisional Ionization

Ultraintense laser-driven relativistic electrons provide a way of heating matter to high energy density states related to many applications. However, the transport of relativistic electrons in solid targets has not been understood well yet, especially in dielectric targets. We present the first detailed two-dimensional particle-in-cell simulations of relativistic electron transport in a silicon target by including the field ionization and collisional ionization processes. An ionization wave is found propagating in the insulator, with a velocity dependent on laser intensity and slower than the relativistic electron velocity. Widely spread electric fields in front of the sheath fields are observed due to the collective effect of free electrons and ions. The electric fields are much weaker than the threshold electric field of field ionization. Two-stream instability behind the ionization front arises for the cases with laser intensity greater than $5\times 10^{19}~\text{W}/\text{cm}^{2}$ that produce high relativistic electron current densities.

scholarly journals On the seasonal dependence of relativistic electron fluxes

2010 ◽  
Vol 28 (5) ◽  
pp. 1101-1106 ◽  
Author(s):  
S. G. Kanekal ◽  
D. N. Baker ◽  
R. L. McPherron
Keyword(s):  
Solar Cycle ◽  
Relativistic Electron ◽  
Solar Wind Speed ◽  
Time Lag ◽  
Outer Zone ◽  
Cycle Phase ◽  
Relativistic Electrons ◽  
Phase Dependence ◽  
Autumnal Equinox ◽  
Seasonal Dependence

Abstract. The nature of the seasonal dependence of relativistic electron fluxes in the Earth's outer zone is investigated using 11 years of data from sensors onboard the SAMPEX spacecraft. It is found that, the relativistic electron fluxes show a strong semiannual modulation. However, the highest electron fluxes occur at times well away from the nominal equinoxes, lagging them by about 30 days. The time lag also shows a solar cycle phase dependence for the peak fluxes. The electron peak fluxes lag the vernal equinox by almost 60 days during the ascending phase of the solar cycle while the time lag near the autumnal equinox remains unchanged. The observed times of the peak electron fluxes during the descending phase of the solar cycle agrees most closely with the Russel-Mcpherron effect and less so with the equinoctial effect even after including propagation effects for finite solar wind speed. The observed times of the electron peaks are in disagreement with the axial effect. The asymmetrical response of the relativistic electrons during the ascending part of the solar cycle remains a puzzle.

scholarly journals On the semi-annual variation of relativistic electrons in the outer radiation belt

2021 ◽  
Author(s):  
Christos Katsavrias ◽  
Constantinos Papadimitriou ◽  
Sigiava Aminalragia-Giamini ◽  
Ioannis A. Daglis ◽  
Ingmar Sandberg ◽  
...  
Keyword(s):  
Relativistic Electron ◽  
Radiation Belt ◽  
Annual Variation ◽  
Phase Relationship ◽  
Relativistic Electrons ◽  
Solar Cycles ◽  
Outer Radiation Belt ◽  
Cross Wavelet Analysis ◽  
Cycle 24 ◽  
Broad Energy

Abstract. The nature of the semi-annual variation in the relativistic electron fluxes in the Earth’s outer radiation belt is investigated using Van Allen Probes (MagEIS and REPT) and GOES (EPS) data during solar cycle 24. We perform wavelet and cross-wavelet analysis in a broad energy and spatial range of electron fluxes and examine their phase relationship with the axial, equinoctial and Russell-McPherron mechanisms. It is found that the semi-annual variation in the relativistic electron fluxes exhibits pronounced power in the 0.3–4.2 MeV energy range at L-shells higher than 3.5 and, moreover, it exhibits an in-phase relationship with the Russell-McPherron effect indicating the former is primarily driven by the latter. Furthermore, the analysis of the past 3 solar cycles with GOES/EPS indicates that the semi-annual variation at geosynchronous orbit is evident during the descending phases and coincides with periods of a higher (lower) HSS (ICME) occurrence.

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