Orbit-Averaged Trapped Proton Fluxes

The TRP module calculates omnidirectional differential trapped proton fluxes which are averaged over the whole mission trajectory (if the whole-orbit option has been selected) or over segments of the trajectory (if the orbital segments option has been selected). Average fluxes are written to output files with names of the form something_ave.tr*, where "something" is the rootname you specify.

The TRP module accumulates this average using an orbit generator. (See limitations for more details on the orbit generator.) The generator tracks the mission through the number of orbits you specify. On each orbit, the trapped proton flux is evaluated at 200 locations, which are equally spaced in time.

Orbit-averaged fluxes are actually accumulated in a number of integral channels, which give the proton flux (in protons/m²-s-sr) above a specific energy. At the end of the orbital accumulation, the resulting spectrum is then numerically differentiated, to obtain a differential spectrum (that is, protons/m²-s-sr-MeV vs. kinetic energy in MeV). This procedure is considered more accurate than numerically differentiating at each location and then averaging the differential spectra.

Orbit-averaged fluxes are returned only above 1 MeV (at the surface of the spacecraft). However, the very low energy fluxes (below ~3 MeV) are widely believed to be unreliable. See limitations.

TRP also produces a peak trapped proton spectrum