A new global electron and proton specification model: GREEN
Abstract
The well known AP8 and AE8 NASA models are commonly used in the industry to specify the radiation belt environment. Unfortunately, there are some limitations in the use of these models, first due to the covered energy range, but also because in some regions of space, there are discrepancies between the predicted average values and the measurements. Moreover, new US models AE9/AP9 were developed a few years ago. These models are better than AE8/AP8 in some cases but are still very controversial in some regions of radiation belts. Therefore, our aim is to develop a radiation belt model, covering a large region of space and energy, from LEO altitudes to GEO and above, and from plasma to relativistic particles. GREEN (Global Radiation Earth ENvironment) is a model providing fluxes at any location between L*=1 and L*=8 all along the magnetic field lines and for any energy between 1 keV to 10 MeV for electrons and between 1 keV and 800 MeV for protons. This model is composed of global models: AE8/AP8 and SPM for low energies and local models. Ten years ago we developed the IGE-2006 model for geostationary orbit electrons. This model was proven to be more accurate than AE8, and used commonly in the industry, covering a broad energy range, from 1keV to 5MeV. From then, a proton model for geostationary orbit, called IGP, was also developed for material applications. These models at geostationary orbit were followed by the OZONE model covering a narrower energy range but the whole outer electron belt, a SLOT model to assess average electron values for 2<L*<4, and finally the OPAL model, which provides high energy proton flux values at low altitudes (up to 1336 km). As most of these models were developed using more than a solar cycle of measurements, these ones being checked, cross calibrated and filtered, we have no doubt that the obtained averages are more accurate than AP8 and AE8 for these particular locations. These local models were validated along different orbit with independent data sets or effect measurements.GREEN is not just a collection of various models, it calculates the electron and proton fluxes from the more relevant existing model for a given energy and a given location. Moreover, some existing models can be updated or corrected in GREEN. In 2017, a new version of GREEN was developed (GREEN-V1), in which a new SLOT model (up to L*=5) and a correction of AE8 model at high energy for L*<2.5 have been implemented. Up to now, some efforts have mainly been made to better estimate high energy electron fluxes, but in 2018, some improvements will be done for energetic proton fluxes and low energy protons and electrons fluxes. Of course, the way the model is developed is well suited to future enhancement with new models developed locally or under international partnerships. In a near future, GREEN model would be accessible for space industry in the OMERE software.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E3120S