Table of Contents ECSS Model Page
Background Information Radiation sources and effects
Solar particle models

SPENVIS can run solar particle fluence models to predict fluences. The models yield fluences outside the magnetosphere, which are then corrected for magnetic shielding.

In order to run these models, a spacecraft trajectory is needed. If no trajectory has been generated yet, the orbit generator should be run first.

The input parameters and options for the Long-term solar particle fluence models are described below. When the input form has been completed, pressing the button will start the calculation and bring up the "Results" page.

The button calls up the model selection page for consecutive runs of multiple models. This feature is available for advanced users only.

Warning: using these buttons deletes all existing output from the Long-term solar particle fluence models and from any model that uses this output, in order to ensure consistency in the outputs.

Input parameters

Model selection

The following models for solar particle fluences are available in SPENVIS:

for solar protons:

for solar heavy ions:

Prediction period

The prediction period used for the particle models is the total mission length. SPENVIS Will calculate the portion of the prediction period in the solar maximum phases of the solar cycles covered by the mission, using the mission start date as a starting point. When the mission duration in the solar maximum phase is smaller than 1 year, the fluences for 1 year are used as a conservative estimate.

The 7-year period of maximum activity is defined as [year of max. - 2.5, year of max. + 4.5]

Advanced users have the option to override the length of the prediction period and the start of the period with respect to the start of the solar maximum phase.

Confidence level

The confidence level is the probability (in %) that the predicted proton fluences will not be exceeded. Please consult the guidelines for selecting appropriate confidence levels for the JPL-91/Rosenqvist et al. (2005, 2007) and King models. The lower limit for the confidence level is 50%. The upper limit depends on the selected model; for the ESP worst case event model, the value 100% is allowed: it corresponds to an upper limit that is consistent with long-term historical evidence.

Number of events

When the King model is used, the number of anomalous and ordinary events can be specified directly instead of having it derived from Burrell statistics. SPENVIS then calculates the confidence level corresponding to the probability that the specified number of events will not be exceeded.

Magnetic shielding

Solar particle fluences are shielded by the planet's magnetic field if present. This shielding effect can be turned off to simulate the environment outside the magnetosphere.

The magnetic shielding of solar particles is lower during stormy conditions than for a quiet magnetosphere. A selection between these conditions is available only for Earth.

Interplanetary missions

Currently in SPENVIS, for interplanetary missions the solar particle fluences are scaled by a factor calculated as the mean value over the mission: r-2 for r < 1AU and 1 for r > 1AU.

Results

The Long-term solar particle fluence models produce the files listed in the table below. A description of the file formats can be brought up by clicking on their description in the table.

The report file spenvis_sep.html contains the input parameters and summary tables. The spectrum file spenvis_sef.txt contains the fluence spectrum, and the spenvis_seo.txt file contains the attenuation factor for each orbital point and for each energy.

Output files generated by the Long-term solar particle fluence models
File name Description
spenvis_sep.html Report file
spenvis_sef.txt Fluence spectra for SHIELDOSE(-2), NIEL, EQFLUX, MULASSIS LONGUPSET
spenvis_seo.txt Attenuation factor

To generate plots, select the plot type(s), options and graphics format, and click the or button. The current page will be updated with the newly generated plot files.

The button calls up the output page for consecutive runs of multiple models. This button only appears when the Long-term solar particle fluence models have been included in the combined model run selection. This feature is available for advanced users only.

References

Feynman, J., G. Spitale, J. Wang, and S. Gabriel, Interplanetary Proton Fluence Model: JPL 1991, J. Geophys. Res., 98, 13,281-13,294, 1993.

Glover, A., Hilgers, A., Rosenqvist, L. and Bourdarie, S.: Interplanetary proton cumulated fluence model update, Advances in Space Research, Volume 42, Issue 9, 3 November 2008, Pages 1564-1568

Jiggens, P., Varotsou, A., Truscott, P., Heynderickx, D., Lei, F., Evans, H. & Daly, E., The Solar Accumulated and Peak Proton and Heavy Ion Radiation Environment (SAPPHIRE) Model, IEEE Transactions on Nuclear Science, Volume 65, Issue 2, 2018.

King, J. H., Solar Proton Fluences for 1977-1983 Space Missions, J. Spacecraft Rockets, 11, 401, 1974.

Rosenqvist, L., Hilgers, A., Evans, H., Daly, E.A., Hapgood, M., Stamper, R., Zwickl, R., Bourdarie, S. and Boscher, D. : Toolkit for Updating Interplanetary Proton-Cumulated Fluence Models, Journal of Spacecraft and Rockets, Vol. 42, No. 6, 2005.

Xapsos, M. A., G. P. Summers, J. L. Barth, E. G. Stassinopoulos, and E. A. Burke, Probabillity Model for Worst Case Solar Proton Event Fluences, IEEE Trans. Nucl. Sci., 46, 1481-1485, 1999.

Xapsos, M. A., G. P. Summers, J. L. Barth, E. G. Stassinopoulos, and E. A. Burke, Probabillity Model for Cumulative Solar Proton Event Fluences, IEEE Trans. Nucl. Sci., 47, 486-490, 2000.

M. A. Xapsos, C. Stauffer, T. Jordan, J. L. Barth, and R. A. Mewaldt, Model for Cumulative Solar Heavy Ion Energy and Linear Energy Transfer Spectra, IEEE Trans. Nucl. Sci., 54, No. 6, December 2007.

Last update: Fri, 27 Apr 2018