Bounce-averaged diffusion coefficients due to resonant interaction of the outer radiation belt electrons with oblique chorus waves computed in a realistic magnetic field model

2012 ◽  
Vol 117 (A7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Ksenia G. Orlova ◽  
Yuri Y. Shprits ◽  
Binbin Ni
Keyword(s):  
Magnetic Field ◽  
Diffusion Coefficients ◽  
Radiation Belt ◽  
Field Model ◽  
Resonant Interaction ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Magnetic Field Model ◽  
Radiation Belt Electrons

scholarly journals Simulation of the outer radiation belt electrons near geosynchronous orbit including both radial diffusion and resonant interaction with Whistler-mode chorus waves

2005 ◽  
Vol 32 (19) ◽  
pp. n/a-n/a ◽  
Author(s):  
Athena Varotsou ◽  
Daniel Boscher ◽  
Sebastien Bourdarie ◽  
Richard B. Horne ◽  
Sarah A. Glauert ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Resonant Interaction ◽  
Radial Diffusion ◽  
Geosynchronous Orbit ◽  
Outer Radiation Belt ◽  
Whistler Mode ◽  
Chorus Waves ◽  
Radiation Belt Electrons

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

<p>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’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‐latitude chorus waves can tip the balance between acceleration and loss toward acceleration, or alternatively, the increase in high‐latitude waves can result in a net loss of MeV electrons. Variations in high‐latitude chorus may account for some of the variability of MeV electrons. </p><p>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 “Internal Charging Effects and the Relevant Space Environment” 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 ‘fly’ 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.</p>

On the Use of Different Magnetic Field Models for Simulating the Dynamics of the Outer Radiation Belt Electrons During the October 1990 Storm

2019 ◽  
Vol 124 (8) ◽  
pp. 6453-6486 ◽  
Author(s):  
Vivien Loridan ◽  
Jean‐François Ripoll ◽  
Weichao Tu ◽  
Gregory Scott Cunningham
Keyword(s):  
Magnetic Field ◽  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Radiation Belt Electrons

scholarly journals Radiation belt data assimilation of a moderate storm event using a magnetic field configuration from the physics-based RAM-SCB model

2014 ◽  
Vol 32 (5) ◽  
pp. 473-483 ◽  
Author(s):  
Y. Yu ◽  
J. Koller ◽  
V. K. Jordanova ◽  
S. G. Zaharia ◽  
H. C. Godinez
Keyword(s):  
Magnetic Field ◽  
Data Assimilation ◽  
Radiation Belt ◽  
Field Model ◽  
Field Configuration ◽  
Storm Event ◽  
Magnetic Field Configuration ◽  
Magnetic Field Model ◽  
Global Magnetic Field

Abstract. Data assimilation using Kalman filters provides an effective way of understanding both spatial and temporal variations in the outer electron radiation belt. Data assimilation is the combination of in situ observations and physical models, using appropriate error statistics to approximate the uncertainties in both the data and the model. The global magnetic field configuration is one essential element in determining the adiabatic invariants for the phase space density (PSD) data used for the radiation belt data assimilation. The lack of a suitable global magnetic field model with high accuracy is still a long-lasting problem. This paper employs a physics-based magnetic field configuration for the first time in a radiation belt data assimilation study for a moderate storm event on 19 December 2002. The magnetic field used in our study is the magnetically self-consistent inner magnetosphere model RAM-SCB, developed at Los Alamos National Laboratory (LANL). Furthermore, we apply a cubic spline interpolation method in converting the differential flux measurements within the energy spectrum, to obtain a more accurate PSD input for the data assimilation than the commonly used linear interpolation approach. Finally, the assimilation is done using an ensemble Kalman filter (EnKF), with a localized adaptive inflation (LAI) technique to appropriately account for model errors in the assimilation and improve the performance of the Kalman filter. The assimilative results are compared with results from another assimilation experiment using the Tsyganenko 2001S (T01S) magnetic field model, to examine the dependence on a magnetic field model. Results indicate that the data assimilations using different magnetic field models capture similar features in the radiation belt dynamics, including the temporal evolution of the electron PSD during a storm and the location of the PSD peak. The assimilated solution predicts the energy differential flux to a relatively good degree when compared with independent LANL-GEO in situ observations. A closer examination suggests that for the chosen storm event, the assimilation using the RAM-SCB predicts a better flux at most energy levels during storm recovery phase but is slightly worse in the storm main phase than the assimilation using the T01S model.

Methodology for calculation of radial diffusion coefficients for a relativistic electron population from hybrid-Vlasov simulation

2021 ◽  
Author(s):  
Harriet George ◽  
Emilia Kilpua ◽  
Adnane Osmane ◽  
Urs Ganse ◽  
Solene Lejosne ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Radiation Belt ◽  
Time Derivative ◽  
Distribution Functions ◽  
Radial Diffusion ◽  
Outer Radiation Belt ◽  
Electron Population ◽  
Radial Diffusion Coefficient

<p>The relative importance of radial diffusion and local acceleration to the dynamics of outer radiation belt electron populations is an open question in radiation belt physics. A key component of this discussion is the calculation of the radial diffusion coefficients, which quantify the effect of radial diffusion on an electron population. However, there is currently a broad range of radial diffusion coefficient values in the literature, which presents difficulties when determining the dominant process governing radiation belt energisation. Here we develop a methodology for the calculation of radial diffusion coefficients using Vlasiator, a 5D hybrid-Vlasov simulation of near-Earth space, and calculate the radial diffusion coefficients for a 10 MeV electron population at multiple locations within the outer radiation belt.</p><p> </p><p>Vlasiator currently models ions as velocity distribution functions and electrons as a magnetohydrodynamic fluid, so the drift motion of the electron population can not be directly studied. However, the ion dynamics accurately determine the magnetic field in the inner magnetosphere, and the spatial and temporal magnetic field variations can be used to calculate the radial diffusion coefficient of a population according to principles outlined in Lejosne et. al. 2020.<span>  </span>Four magnetic field isocontours in the outer radiation belt are used to model the guiding centre drift contours of an electron population, and the corresponding Roederer L-star coordinates are calculated from the magnetic flux through each of these drift contours. The variation of the L-stars over time are calculated from population-specific variables and the Lagrangian magnetic field time derivative along the magnetic isocontours. The radial diffusion coefficients for the 10 MeV electron population are then calculated at each of these L-stars and compared to the literature. This methodology produces radial diffusion coefficients from Vlasiator that have the expected L-shell dependence and are consistent with the literature, including studies based on satellite measurements of radiation belt electrons. These results indicate that this is a valid methodology for the calculation of radial diffusion coefficients, and can therefore be extended to evaluate the radial diffusion coefficients in different solar wind conditions and at more L-stars.</p>

Influence of wave normal angle on gyroresonance between chorus waves and outer radiation belt electrons

2013 ◽  
Vol 56 (11) ◽  
pp. 2681-2689 ◽  
Author(s):  
YuanHui Ding ◽  
ZhaoGuo He ◽  
ZeLong Zhang ◽  
FuLiang Xiao
Keyword(s):  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Chorus Waves ◽  
Radiation Belt Electrons ◽  
Wave Normal ◽  
Normal Angle

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>

Sign in / Sign up

Export Citation Format

Share Document