Modes for Running AE9/AP9/SPM

The AE9/AP9/SPM model suite introduces data-based statistics for estimates of the particle environment hazard, in contrast to legacy models which often provided estimates based only on a median environment state. AE9/AP9/SPM provides three mode options to variously access this capability:

Mean

using the mean flux maps with no variance statistics (analogous to most legacy models);

Perturbed mean

run as scenarios with fluxes perturbed by uncertainties in measurements and in gap-filling/extrapolation results;

Monte Carlo

run as scenarios representing the perturbed mean uncertainties but with the addition of space weather variability (not available for SPM).

In perturbed mean and Monte Carlo modes, each scenario run is randomly initialized to provide one realization of the expected environment. Statistics compiled from multiple scenarios then yield estimates of the uncertainty of the environment.

Specification desired	Run mode	Duration	Combination of results
Total dose	Perturbed mean	several orbits or days	SPME + AE9, SPMH + AP9 + solar*
Displacement damage (proton fluence)	Perturbed mean	several orbits or days	AP9 + solar*
Proton SEE (proton worst case)	Monte Carlo	full mission	AP9 + solar*
Internal charging (electron worst case)	Monte Carlo	full mission	AE9

The table above summarizes choices of AE9/AP9/SPM model runs suggested for typical specifications:

Note (*): solar particles are not currently included in AE9/AP9/SPM; a separate model must be used for estimates of solar protons, see e.g. M. A. Xapsos, P. M. O'Neill and T. P. O'Brien, “Near-Earth space radiation models,” IEEE Trans. Nucl. Sci., 60(3):1691-1705 (2013). [1]