scholarly journals OMEP-EOR: A MeV proton flux specification model for Electric Orbit Raising missions

2021 ◽  
Author(s):  
Antoine Brunet ◽  
Angélica Sicard ◽  
Constantinos Papadimitriou ◽  
Didier Lazaro ◽  
Pablo Caron
Keyword(s):  
Radiation Belt ◽  
Temporal Dynamics ◽  
Radiation Belts ◽  
Proton Flux ◽  
Radiation Environment ◽  
Solar Arrays ◽  
Proton Fluxes ◽  
Van Allen Probes ◽  
Spectrum Distribution ◽  
Gp Model

Electric Orbit Raising (EOR) for telecommunication satellites has allowed significant reduction in on-board fuel mass, at the price of extended transfer durations. These relatively long transfers, which usually span a few months, cross large spans of the radiation belts, resulting in significant exposure of the spacecraft to space radiations. Since they are not very populated, the radiation environment of intermediate regions of the radiation belts is less constrained than on popular orbits such as LEO or GEO on standard environment models. In particular, there is a need for more specific models for the MeV energy range proton fluxes, responsible for solar arrays degradations, and hence critical for EOR missions. As part of the ESA ARTES program, ONERA has developed a specification model of proton fluxes dedicated for EOR missions. This model is able to estimate the average proton fluxes between 60 keV and 20MeV on arbitrary trajectories on the typical durations of EOR transfers. A global statistical model of the radiation belts was extracted from the Van Allen Probes (RBSP) RBSPICE data. For regions with no or low sampling, simulation results from the Salammbô radiation belt model were used. A special care was taken to model the temporal dynamics of the belts on the considered mission durations. A Gaussian Process (GP) model was developed, allowing to compute analytically the distribution of the average fluxes on arbitrary mission durations. Satellites trajectories can be flown in the resulting global distribution, yielding the proton flux spectrum distribution as seen by the spacecraft. We show results of the model on a typical EOR trajectory. The obtained fluxes are compared to the standard AP8 model, the AP9 model, and validated using the THEMIS satellites data.We illustrate the expected e ect on solar cell degradation, where our model is showing an increase of up to 20% degradation prediction compared to AP8.

A Proton Flux Model Dedicated to Solar Arrays Degradations on Electric Orbit Raising Missions

2021 ◽  
Author(s):  
Antoine Brunet ◽  
Angélica Sicard ◽  
Constantinos Papadimitriou ◽  
Didier Lazaro
Keyword(s):  
Radiation Belt ◽  
Temporal Dynamics ◽  
Radiation Belts ◽  
Radiation Environment ◽  
Solar Arrays ◽  
Proton Fluxes ◽  
Van Allen Probes ◽  
Orbital Transfers ◽  
Flux Model ◽  
Simulation Results

<p>Electric Orbit Raising (EOR) for telecommunication satellites has allowed significant reduction in onboard fuel mass, at the price of extended transfer durations. These relatively long orbital transfers, which can take up to a few months, equatorially cross most of the radiation belts, resulting in significant exposure of the spacecraft to space radiations. Since there are not covered by many spacecrafts, the radiation environment of intermediate regions of the radiation belts is less known than on popular orbits such as LEO or GEO. In particular, there is a need for more specific models for the MeV energy range proton fluxes, responsible for solar arrays degradations. We present a model of proton fluxes dedicated for EOR missions that was developped as part of the ESA ARTES program. This model is able to estimate the average proton fluxes between 60 keV and 10MeV on arbitrary trajectories on the typical durations of EOR transfers. A global statistical model of the radiation belts was extracted from the Van Allen Probes (RBSP) RBSPICE data and enriched by simulation results from the Salammbô radiation belt model were used. A special care was taken to model the temporal dynamics of the proton belt, allowing to compute analytically the distribution of the average fluxes on arbitrary EOR missions.</p>

Acceleration and Loss of Ultra-relativistic Electrons in the Earth Van Allen Radiation Belts

2021 ◽  
Author(s):  
Yuri Shprits ◽  
Hayley Allison ◽  
Alexander Drozdov ◽  
Dedong Wang ◽  
Nikita Aseev ◽  
...  
Keyword(s):  
Geomagnetic Storms ◽  
Local Heating ◽  
Rest Mass ◽  
Radiation Belts ◽  
Radiation Environment ◽  
Relativistic Electrons ◽  
Horizon 2020 ◽  
Probabilistic Forecasts ◽  
Van Allen Probes ◽  
Loss Mechanisms

<p>Measurements from the Van Allen Probes mission clearly demonstrated that the radiation belts cannot be considered as a bulk population above approximately electron rest mass. Ultra-relativistic electrons (~>4Mev) form a new population that shows a very different morphology (e.g. very narrow remnant belts) and slow but sporadic acceleration.</p><p>We show that acceleration to multi-MeV energies can not only result of a two-step processes consisting of local heating and radial diffusion but occurs locally due to energy diffusion by whistler mode waves. Local heating appears to be able to transport electrons in energy space from 100s of keV all the way to ultra-relativistic energies (>7MeV). Acceleration to such high energies occurs only for the conditions when cold plasma in the trough region is extremely depleted down to the values typical for the plasma sheet.</p><p>There is also a clear difference between the loss mechanisms at MeV and multi MeV energies The difference between the loss mechanisms at MeV and multi-MeV energies is due to EMIC waves that can very efficiently scatter ultra-relativistic electrons, but leave MeV electrons unaffected.</p><p>We also present how the new understanding gained from the Van Allen Probes mission can be used to produce the most accurate data assimilative forecast. Under the recently funded EU Horizon 2020 Project Prediction of Adverse effects of Geomagnetic storms and Energetic Radiation (PAGER) we will study how ensemble forecasting from the Sun can produce long-term probabilistic forecasts of the radiation environment in the inner magnetosphere.</p>

scholarly journals Radiation Belt Processes in a Declining Solar Cycle

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
A. Ukhorskiy ◽  
B. Mauk ◽  
D. Sibeck ◽  
R. Kessel
Keyword(s):  
Solar Cycle ◽  
Radiation Belt ◽  
Radiation Belts ◽  
Van Allen Probes ◽  
Earth's Radiation Belts

The Van Allen Probes began an extended mission in November to advance understanding of Earth's radiation belts.

Increase in seismic activity near the footprints of new radiation belts forming after geomagnetic storms

2021 ◽  
Author(s):  
Nursultan Toyshiev ◽  
Galina Khachikyan ◽  
Beibit Zhumabayev
Keyword(s):  
Geomagnetic Storm ◽  
Seismic Activity ◽  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Radiation Belts ◽  
Tien Shan ◽  
Relativistic Electrons ◽  
Inner Magnetosphere ◽  
Van Allen Probes ◽  
Northern Tien Shan

<p>Recently, attention was drawn [1] that after geomagnetic storms that cause formation of new radiation belts in slot region or in the inner magnetosphere, after about 2 months, there is an increase in seismic activity near the footprints of geomagnetic lines of new radiation belts. More detailed studies showed [2] that on May 30, 1991, an earthquake M=7.0 occurred in Alaska with (54.57N, 161.61E) near the footprint of geomagnetic line L = 2.69 belonging to new radiation belt, which was observed by the CRRES satellite [3] around geomagnetic lines 2<L<3 after geomagnetic storm on March 24, 1991. After geomagnetic storm on September 3, 2012, the Van Allen Probes satellites observed new radiation belt around 3.0≤L≤3.5 [4], and about 2 months later, on October 28, 2012, earthquake M=7.8 occurred off the coast of Canada (52.79N, 132.1W) near the footprint of geomagnetic line L=3.32 belonging to the new radiation belt. Also, Van Allen Probes observed new radiation belt around L=1.5-1.8 after geomagnetic storm on June 23, 2015 [5], and ~2 months later, in September 2015, seismic activity noticeably increased near the footprint of these geomagnetic lines. We consider variations in seismic activity in connection with the strongest geomagnetic storms in 2003 with Dst~- 400 nT (Halloween Storm) and the formation of a belt of relativistic electrons in the inner magnetosphere around L~1.5 existed until the end of 2005 as observed SAMPEX [6]. Analysis of data from the USGS global seismological catalog showed that near the footprint of geomagnetic lines L=1.4-1.6 the number of earthquakes with M≥4.5 increased in 2003-2004 by ~70% compared with their number in two previous years. On the Northern Tien Shan, on December 1, 2003 a strong for the region earthquake M=6.0 occurred on the border of Kazakhstan and China (42.9N, 80.5E) near the footprint of L = 1.63, adjacent to the new radiation belt.</p>

Electron filling and proton loss in radiation belts and SAA during 2018 storm based on ZH-1 satellite observations

2021 ◽  
Author(s):  
Zhenxia Zhang
Keyword(s):  
Geomagnetic Storm ◽  
Radiation Belt ◽  
Electron Flux ◽  
Outer Boundary ◽  
Energetic Electron ◽  
High Energy ◽  
Radiation Belts ◽  
High Energy Particle ◽  
Van Allen Probes ◽  
Proton Loss

<p>Based on data from the ZH-1 satellites, companied with Van Allen Probes and NOAA observations, we analyze the high energy particle evolutions in radiation belts, slot region and SAA during August 2018 major geomagnetic storm (minimum Dst ≈ −190 nT). </p><p>  1) Relativistic electron enhancements in extremely low L-shell regions (reaching L ∼ 3) were observed during storm. Contrary to what occurs in the outer belt, such an intense and deep electron penetration event is rare and more interesting. Strong whistler-mode (chorus and hiss) waves, with amplitudes 81–126 pT, were also observed in the extremely low L-shell simultaneously (reaching L ∼ 2.5) where the plasmapause was suppressed. The bounce-averaged diffusion coefficient calculations support that the chorus waves can play a significantly important role in diffusing and accelerating the 1–3 MeV electrons even in such low L-shells during storms.</p><p>2) A robust evidence is clearly demonstrated that the energetic electron flux with energy 30∼600 keV are increased by 2∼3 times in the inner radiation belt near equator and SAA region on dayside during the major geomagnetic storm. This is the first time that the 100s keV electron flux enhancement is reported to be potentially induced by the interaction with magnetosonic waves in extremely low L-shells (L<2) observed by Van Allen Probes. Proton loss in outer boundary of inner radiation belt takes place in energy of 2~220 MeV extensively during the occurrence of this storm but the loss mechanism is energy dependence which is consistent with some previous studies. It is confirmed that the magnetic field line curvature scattering plays a significant role in the proton loss phenomenon in energy 30-100 MeV during this storm. This work provides a beneficial help to comprehensively understand the charged particles trapping and loss in SAA region and inner radiation belt dynamic physics.</p>

Statistical study of the storm time radiation belt evolution during Van Allen Probes era: CME- versus CIR-driven storms

2017 ◽  
Vol 122 (8) ◽  
pp. 8327-8339 ◽  
Author(s):  
Xiao-Chen Shen ◽  
Mary K. Hudson ◽  
Allison N. Jaynes ◽  
Quanqi Shi ◽  
Anmin Tian ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Statistical Study ◽  
Van Allen Probes

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 The effects of the big storm events in the first half of 2015 on the radiation belts observed by EPT/PROBA-V

2016 ◽  
Vol 34 (1) ◽  
pp. 75-84 ◽  
Author(s):  
V. Pierrard ◽  
G. Lopez Rosson
Keyword(s):  
Charged Particle ◽  
High Resolution ◽  
Geomagnetic Storm ◽  
Energetic Particle ◽  
High Energy ◽  
Radiation Belts ◽  
Radiation Environment ◽  
Storm Event ◽  
Storm Events ◽  
Particle Radiation

Abstract. With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500–600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts.

scholarly journals Variation of Proton Flux with Atmospheric Depth Between 10 and 50 g/cm2 at l = 47° S. Geomagnetic

1965 ◽  
Vol 18 (1) ◽  
pp. 59 ◽  
Author(s):  
KKM Wu ◽  
BSK Chow
Keyword(s):  
Proton Flux ◽  
Atmospheric Depth ◽  
Nuclear Emulsions ◽  
Proton Fluxes

Proton fluxes at atmospheric depths between 10 and 50 g/cm2 have been measured using nuclear emulsions during a series of balloon flights over Melbourne (A = 47� S. geomagnetic) in the period November 1961-April 1962. The proton flux J(x) decreases with increasing depth within this region. It can be represented by the relation log J(x) = (3�05�0�02)-(2�36�0�66)xlO-3x and, when extrapolated, gives the flux at the top of the atmosphere to be 1120�50 protons m-2 steradian-1 S-l.

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