The input parameters and options for the model are
described below. When the input form has been completed, pressing the
button will start the calculation and
bring up the "Results" page.
The second parameter to be entered is the
spacecraft shielding thickness,
in units of aluminium or aluminium equivalent thickness.
The cosmic ray and solar energetic particle environment contains ions of all
elements. The composition is specified by means of a lower and upper limit
for the elements to be considered in the calculation.
The upper limit should be greater than or equal to the lower limit.
The environment models currently implemented are those of CREME-86. For the galactic cosmic ray flux also the MSU model
has been implemented in two versions: the standard model ISO-15390 and the model by R.A. Nymmik et al. (1996).
The latter includes a rising flux at very low energies (around 10 MeV/nucleon).
The option "solar activity data" (only available when using the MSU model) allows the user to run the model for different epochs:
- Solar minimum (May 1996), corresponding to the epoch of solar minimum conditions
- mission epoch, corresponding to the epoch for which the orbit is generated
- user defined (only for the advanced user!)
By default tabulated solar cycle data (yearly sunspot numbers) from the year 1957 until 2007 are used. For future epochs
the solar cycle is propagated by substracting 22*n years from the epoch. As an advanced user you can enter
the solar cycle data. In this case one of the required user inputs is the sunspot number
at (epoch - lag) where the lag is the delay time of the cosmic ray particle flux variations relative to the solar activity variations.
We remark that (only) in this case the lag time is taken constant while it normally depends on the particle rigidity.
outside the magnetosphere depends on the phase of the solar cycle and on
flare activity. The phase of the solar cycle is derived from the
orbit start date.
Cosmic ray and solar energetic particles are attenuated by the
of the Earth's magnetic field. Geomagnetic shielding is calculated for quiet
or disturbed conditions of the magnetosphere, or can be ignored altogether,
for instance to simulate interplanetary conditions.
SPENVIS Checks whether the
trapped proton models have
been run for the current project. If a spectrum file is found, and if the
user has included protons in the environment composition, the trapped proton
fluxes can be added to the solar and cosmic rays proton fluxes. The user also
has the option to ignore the trapped proton fluxes.
The report file spenvis_lop.html contains the input parameters
and summary tables.
The spectrum file spenvis_lof.txt
contains the proton and LET spectra averaged over each mission segment and
the total mission averaged spectra.
The optional spectrum file spenvis_loo.txt
contains, for each orbital point, the full proton and LET spectra.
To generate plots, select the plot
type(s), options and
and click the button.
The current page will be updated with the newly generated plot files.