ESP & Psychic Solar Flare Models

1. ESP & Psychic Solar Flare Models • The Problem • The ESP Model of Solar Protons • Psychic Model Tom Diehl January 5, 2005

2. 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 (from galactic protons) to 200 rad/day (from the worst solar flare). • We need a better model if we are to provide a spec. for radiation dose.

3. Solar Cycle Projection • Solar flares and coronal mass ejections originate with the “sunspots” • Plot on left is projected sunspot count. • There’s an 11Yr solar cycle. • NGST Radiation Environment: Barth, Isaacs, Poivey http://www.ngst.nasa.gov/public/unconfigured/doc_0570/rev_04/ngstradenv2.pdf Est. Sunspot Activity vs. Year (2009-2020)

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. Simple Interface:

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.) • The 100 to 300 MeV part is an extrapolation. 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 1988 to 2020 and 50% or higher c.l. flux. • Plot is “Integral Flux”. Integral Flux (> MeV) 99 95 90 85 80 50 C.L. (%)

8. Proton Flux 2004-2015 • ESP Model • Differential spectrum produced from the integral plot. The units are : #/cm2/yr at 50% C.L. • Caveat: This ESP isn’t the Spenvis version. It’s the version I got from NASA.

9. Psychic Model • Update to ESP from Mike Xapsos (NASA Goddard) • This guy is one of co-authors of the model. I met him at the IEEE NSREC meeting in Atlanta in July. • This update is called “Psychic” goes 327 MeV and has smoother differential spectrum.

10. Proton Flux – Psychic Model • Average for 11 year cycle with 7 years at solar max and 4 years at solar min. • # Protons above 11 51100 MeV is: C.L. (%) #/cm2/s 50 93.9 7.81.3 • These are 2-3x higher than the ESP Model at k.e. > 50 MeV

11. ESP vs. Psychic • Comparison based on 8 y @ solar max and 3 y @ solar min.

12. “MARS 15” and Psychic Results • NVM inc. made a new MARS release in November. • I picked that up, incorporated the SNAP model and reproduced the previous results. • I ran 20M “Psychic protons” using the average flux from 7 yrs of solar max and 4 years of solar min. • The silicon received a dose of 0.1 Rad/yr.

13. Summary and Plan • Solar proton model from Mike X. provides solution. Dose was negligible. • Check MARS result • Email to Mike X. with ESP vs. Psychic comparison • Possibly this doesn’t include solar “events”. • Implement the flux from the ESP Model. • Write up results. Est. Feb 16.