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ESP Solar Flare Model

ESP Solar Flare Model. The Problem The ESP Model of Solar Protons 11 Year Average Proton Flux. Tom Diehl 06/30/2004. Solar Cycle Projection. NGST Radiation Environmrnt: Barth, Isaacs, Poivey http://www.ngst.nasa.gov/public/unconfigured/doc_0570/rev_04/ngstradenv2.pdf.

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ESP Solar Flare Model

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  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_0570/rev_04/ngstradenv2.pdf • Solar flares and coronal mass ejections originate with the “sunspots” • Plot on left is projected sunspot count. • See large variation in solar activity. Est. Sunspot Activity vs. Year (2009-2020)

  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/tp209763.pdf has the write-up and http://see.msfc.nasa.gov/ire/model_esp.html provides a link to software distribution.

  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.

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