1. ESP Solar Flare Model The Problem The ESP Model of Solar Protons 11 Year Average Proton Flux Tom Diehl 06/30/2004

2. Solar Cycle Projection NGST Radiation Environmrnt: Barth, Isaacs, Poivey http://www.ngst.nasa.gov/public/unconfigured/doc_0 570/rev_04/ngstradenv2.pdf Est. Sunspot Activity vs. Year (2009-2020) Solar flares and coronal mass ejections originate with the “sunspots” Plot on left is projected sunspot count. See large variation in solar activity.

3. The Problem Creme96 simulation provides –Galactic cosmic ray fluences at solar minimum and solar maximum –Worst 5 minutes, day, & week of solar flares –These are the extrema and the expected radiation dose varies from 7 rads/yr to 200 rad/day. We need a better model if we are to provide a spec. for radiation dose.

4. “Emission of Solar Protons” Model I came across it in an NASA memo “The Radiation Environment … GOES-R Series Satellites”, 417-R-RPT-0027 (March 2004) and in NGST radiation estimates, both by Janet Barth and Mike Xapsos. They referenced their model. http://trs.nis.nasa.gov/archive/00000505/01/tp209 763.pdf has the write-up and http://see.msfc.nasa.gov/ire/model_esp.html provides a link to software distribution. http://trs.nis.nasa.gov/archive/00000505/01/tp209 763.pdf http://see.msfc.nasa.gov/ire/model_esp.html

5. ESP Model & Results Input Ranges 1970- 2020 and 50%-99% Results from 1970 to 1999 are based on actual observations. Results from 2000 on are averaged over previous years in the solar cycle.

6. ESP Model & Results Four part output: Proton Flux vs. C.L. for several C.L. and also the user C.L., same for worst case solar event. Energy range is 1 MeV to 300 MeV (k.e.) 2// TYPE (1=Input,2=Output) 1998,1999,90 //INPUTS (Start Year,End Year,Confidence Level) TOTAL PROTON FLUENCE FOR MISSION Results for a mission of 1998 to 1999.(2 Active Years) GENERAL CONFIDENCE LEVEL TABLE ------------------------------------------------------------------ Integral Proton Fluence(cm^-2) Energy Levels Confidence Levels() (>MeV) 80 85 90 95 99 ------------- --------- --------- --------- --------- --------- 1 2.44E+011 2.89E+011 3.56E+011 4.85E+011 8.68E+011 3 8.62E+010 1.02E+011 1.27E+011 1.74E+011 3.17E+011 5 5.09E+010 6.16E+010 7.82E+010 1.11E+011 2.16E+011... 275 2.03E+007 3.02E+007 4.97E+007 1.04E+008 4.19E+008 300 1.59E+007 2.37E+007 3.91E+007 8.20E+007 3.29E+008

7. Proton Flux 2004-2015 ESP Model provides solar proton flux estimates in energy range 1 to 300 MeV at distance averaged at 1 A.U. Provides any combination of years from 1988xx to 2020 and 50% or higher c.l. flux.

8. ESP Model - Plan Incorporporate this flux into MARS Get an update of the model from Mike Xapsos that goes to higher energy –Overnighter to IEEE conference in Atlanta; I’ve arranged to meet M.X.

9. Summary Obtained “ESP Model” used by experts to simulate proton fluences from solar events in radiation damage simulations for satellites at L2. It solves the extrema problem and will allow us to make reasonable estimates of the doses. I plan to obtain an extension to the model from the authors.