Speaker
Description
Solar Energetic Particles (SEP) events, especially gradual events generated by coronal mass ejections (CMEs), need to be considered by spacecraft designers. SEP events, highly vairable in frequency and magnitude, are the dominant particle radiation hazard for interplanetary missions up to hundreds of MeVs. Given the majority of SEP data available is collected near the Earth environment, physics-based models describing how the magnitude of SEP events varies with the heliocentric radial distance are needed to develop solar energetic particle environment models for missions travelling in the solar system.
In previous projects, we developed the SOLPENCO2 model that provides predictions on the dependence of the peak intensity and fluence of gradual proton events on the heliocentric radial distance between 0.2 au and 1.6 au, and for protons in the energy range from 5 to 300 MeV. The simulations we present here are embedded within the scope of the ESA’s FIRESPELL project. Two of the objectives of this project are to extend the application of the SAPPHIRE-2S particle radiation model to low-energy protons, in the energy range from 50 keV to 5 MeV, and to interplanetary missions travelling within 0.2 au to 10 au from the Sun.
By employing the same shock particle emission model used in the SOLPENCO2, we simulate different SEP events, to reproduce the intensity-time profiles of 26 energy channels for 0.05 MeV to 700 MeV protons. For this, we use the 1-D Shock-and-Particle (SaP) particle transport model. In order to provide predictions of the radial dependence of these modelled events to distances beyond 1.6 au, we have simulated some of the events with the 3D particle transport model PARADISE to account for the perpendicular transport of the particles, by using the same shock particle emission model as for SaP. Next, following the procedure developed during the SEPEM project (sepem.eu), we derived the peak intensities and the event fluences for several observers located at different radial distances which share the same magnetic connection to the solar source.
We present the results of these simulations and discuss the obtained radial dependences and their variation with the different simulation set-ups used.
FIRESPELL is a project funded by ESA (Contract No. 4000142510/23/NL/CRS).
