New Model for the Plasma Electrons Fluxes (Part of GREEN Model)

Abstract

A new specification model of low energy electrons fluxes, included in GREEN model, has been developed at ONERA. This model is based on several data sets, from low altitudes with NOAA-POES measurements to higher altitudes with POLAR, THEMIS and LANL measurements. It provides mean electron fluxes versus L, B/B eq , MLT and energy (for energies between 0.19 keV and few 10s of keV). In this paper, the model is compared to AE9/SPM model and Van Allen Probe measurements.Index Terms-plasma, specification model. I. INTRODUCTIONHE space environment is composed of charged particles: electrons and ions (mainly protons). These particles induce effects on materials used in space systems like the well-known ones of high energy particles (> 30 keV) on electronic devices. But high-energy particles are not the only population to consider. Indeed lower-energy particles (< 30 keV) can create significant damages on surface materials used in space systems (thermal coatings, cover glass …). Those effects are cumulative such as the relevant radiation environment specification is the total fluence of low-energy particles over the entire mission. Currently, the model available to evaluate this low-energy population is part of AE9/AP9 models and is called SPM [1][2].

Improving the Electron Radiation Belt Nowcast and Forecast Using the SafeSpace Data Assimilation Modeling Pipeline

“…The reference Salammbô 3D electron ensemble model uses the following physical processes submodels, mostly similarly to (S. A. Bourdarie & Maget, 2012): The friction and diffusion in Ec and α eq caused by collisions with neutral atoms in the residual atmosphere are computed, based on the formulas from Beutier and Boscher (1995), using the MSIS86 atmospheric density model (Hedin, 1987). The wave‐particle interaction energy and pitch‐angle diffusion coefficients are computed by the WAPI code (Sicard et al., 2008), using the plasma density model and wave distributions as in N. Dahmen et al. (2022).…”

“…FARWEST relies on the same theoretical frame (based on the quasi‐linear theory) followed in the PADIE code (Glauert & Horne, 2005) and the WAPI code (Sicard et al., 2008) and assuming a dipole magnetic field. As the computational cost required to evaluate one configuration of diffusion coefficients was too prohibitive for real‐time forecasting, especially given the large number of ensemble members used in the SafeSpace pipeline, we have developed an innovative computing logic (N. Dahmen et al., 2022) that drastically reduces the computing time of the bounce‐ and drift‐averaged diffusion coefficients, while maintaining the same level of accuracy as ONERA's legacy code WAPI (Sicard et al., 2008).…”

“…The wave‐particle interaction energy and pitch‐angle diffusion coefficients are computed by the WAPI code (Sicard et al., 2008), using the plasma density model and wave distributions as in N. Dahmen et al. (2022).…”

In-Flight Measurements of Radiation Environment Observed by Eutelsat 7C (Electric Orbit Raising Satellite)

“…8. Unlike AE8 model, IGE model (which is integrated in GREEN-e model [15], [20]) takes into account the solar cycle variation. It was therefore expected that this model would be more consistent with our data.…”

GREEN Upper Envelope Model for Energetic Electrons

“…At low energy, the IRENE model corresponds to SPM model for electrons from 1 keV to 40 keV and for protons from 1 keV to 100 keV. In parallel, ONERA have developed another global model: GREEN (Global Radiation Earth Environment) [4] [5] . This model covers a large region of space, from Low Earth Orbit (LEO) altitudes to Geostationary Earth Orbit (GEO) and above, for a wide range of energies from plasma (0.1 keV) to relativistic particles (several MeV for electrons and several hundred of meV for protons).…”