The
FLUMIC
(Flux Model for Internal Charging) model used for internal charging
assessments is integral to the DICTAT internal charging tool but can be applied
separately. FLUMIC describes the electron flux, which has an exponential
dependence on energy E and varies with L, time of year and phase of the solar
cycle. FLUMIC version 1 and 2 covered L-shells above 2,8, i.e. the outer belt
only. The exponential spectrum can a priori be extrapolated down to lower
energy (say a few 100 keV), although for more dynamics in the lower energy
environment more sophisticated models are available. Version 3 of FLUMIC is
broadly similar to FLUMIC version 2 in the outer belt because here it is based
on the same data. However, it also models electron fluxes in the inner belt
(see Annex B.4).
The
FLUMIC v3 model, presented in Annex B.4, has been evaluated with in-flight data and shown to
provide electron fluxes between 0,8 MeV and 2,8 MeV that exceed 95-98% of the
data for L-Shells above 4 Earth Radii. For the Geostationary orbit, the models
provided electron fluences that exceeded 95% of the data points [RD.67].