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Solar Physics

, 293:117 | Cite as

The Solar Electron and Proton Telescope Aboard STEREO – Understanding Proton Spectra

  • S. Wraase
  • B. Heber
  • S. Böttcher
  • N. Dresing
  • P. Kühl
  • R. Müller-Mellin
Article

Abstract

The Solar Electron and Proton Telescope (SEPT) aboard the Solar Terrestrial Relations Observatory (STEREO) is designed to provide the three-dimensional distribution of energetic electrons and protons with good energy and time resolution. Each SEPT instrument consists of two double-ended magnet–foil particle telescopes which cleanly separate and measure electrons in the energy range from 30 keV to 400 keV and protons from 60 keV to 7000 keV. Anisotropy information on a non-spinning spacecraft is provided by two separate but identical instruments: SEPT-E aligned along the Parker spiral magnetic field in the ecliptic plane looking both towards and away from the Sun, and SEPT-NS aligned vertical to the ecliptic plane looking towards North and South. The dual set-up refers to two adjacent sensor apertures for each of the four viewing directions SUN, ANTISUN, NORTH, and SOUTH: one for protons, one for electrons. In this contribution a simulation of SEPT utilizing the GEANT4 toolkit has been set up with an extended instrument model in order to calculate improved response functions of the four different telescopes. Here we applied these response functions to quiet-time periods during the minimum between Solar Cycles 23 and 24 (SC-23 and SC-24) when the flux of ions above 10 MeV is dominated by galactic cosmic rays (GCRs). The corresponding spectra are determined by a force-field approximation and used as input for our calculation, leading to good agreement of the computed ion count rates with measurements of SEPT above 400 keV.

Keywords

Energetic particles, protons Cosmic rays, galactic Instrumental effects 

Notes

Acknowledgements

The STEREO/SEPT project is supported under Grant 50 OC 1302 by the German Bundesministerium für Wirtschaft through the Deutsches Zentrum für Luft- und Raumfahrt (DLR). P.K. has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 637324.

Disclosure of Potential Conflicts of Interest

The authors declare that they have no conflicts of interest.

References

  1. Agostinelli, S.E.: 2003, Geant 4, a simulation toolkit. Nucl. Instrum. Methods Phys. Res., Sect. A, Accel. Spectrom. Detect. Assoc. Equip. 506(3), 250. ADSCrossRefGoogle Scholar
  2. Burger, R.A., Potgieter, M.S., Heber, B.: 2000, Rigidity dependence of cosmic ray proton latitudinal gradients measured by the Ulysses spacecraft: implications for the diffusion tensor. J. Geophys. Res. Space Phys. 105(A12), 27447. DOI. ADSCrossRefGoogle Scholar
  3. Caballero-Lopez, R.A., Moraal, H.: 2004, Limitations of the force field equation to describe cosmic ray modulation. J. Geophys. Res. Space Phys. 109, A01101. DOI. ADS. ADSGoogle Scholar
  4. Gieseler, J., Heber, B., Herbst, K.: 2017, An empirical modification of the force field approach to describe the modulation of galactic cosmic rays close to Earth in a broad range of rigidities. J. Geophys. Res. Space Phys. 122, 10964. DOI. ADS. ADSCrossRefGoogle Scholar
  5. Gleeson, L.J., Axford, W.I.: 1968, Solar modulation of galactic cosmic rays. Astrophys. J. 154, 1011. DOI. ADS. ADSCrossRefGoogle Scholar
  6. Gloeckler, G., Fisk, L.A., Mason, G.M., Hill, M.E.: 2008, Formation of power law tail with spectral index-5 inside and beyond the heliosphere. In: Li, G., Hu, Q., Verkhoglyadova, O., Zank, G.P., Lin, R.P., Luhmann, J. (eds.) Am. Inst. Phys. Conf. Ser., 1039, 367. DOI. ADS. Google Scholar
  7. Gold, R.E., Krimigis, S.M., Hawkins, S.E.I., Haggerty, D.K., Lohr, D.A., Fiore, E., Armstrong, T.P., Holland, G., Lanzerotti, L.J.: 1998, Electron, proton, and alpha monitor on the advanced composition explorer spacecraft. Space Sci. Rev. 86(1), 541. ADSCrossRefGoogle Scholar
  8. Gopalswamy, N., Xie, H., Akiyama, S., Yashiro, S., Usoskin, I.G., Davila, J.M.: 2013, The first ground level enhancement event of solar cycle 24: direct observation of shock formation and particle release heights. Astrophys. J. Lett. 765, L30. DOI. ADS. ADSCrossRefGoogle Scholar
  9. Haggerty, D.K., Roelof, E.C.: 2003, Electron scattering in solid state detectors: Geant 4 simulations. Adv. Space Res. 32, 423. DOI. ADS. ADSCrossRefGoogle Scholar
  10. Kaiser, M.L., Kucera, T.A., Davila, J.M., St. Cyr, O.C., Guhathakurta, M., Christian, E.: 2008, The STEREO mission: an introduction. Space Sci. Rev. 136, 5. DOI. ADS. ADSCrossRefGoogle Scholar
  11. Kühl, P., Banjac, S., Dresing, N., Goméz-Herrero, R., Heber, B., Klassen, A., Terasa, C.: 2015, Proton intensity spectra during the solar energetic particle events of May 17, 2012 and January 6, 2014. Astron. Astrophys. 576, A120. DOI. ADS. CrossRefGoogle Scholar
  12. Mason, G.M., Gloeckler, G.: 2012, Power law distributions of suprathermal ions in the quiet solar wind. Space Sci. Rev. 172(1), 241. DOI. ADSCrossRefGoogle Scholar
  13. Mason, G.M., Gold, R.E., Krimigis, S.M., Mazur, J.E., Andrews, G.B., Daley, K.A., Dwyer, J.R., Heuerman, K.F., James, T.L., Kennedy, M.J., Lefevere, T., Malcolm, H., Tossman, B., Walpole, P.H.: 1998, The ultra-low-energy isotope spectrometer (ULEIS) for the ACE spacecraft. Space Sci. Rev. 86, 409. DOI. ADS. ADSCrossRefGoogle Scholar
  14. Mewaldt, R.A., Davis, A.J., Lave, K.A., Leske, R.A., Stone, E.C., Wiedenbeck, M.E., Binns, W.R., Christian, E.R., Cummings, A.C., de Nolfo, G.A., Israel, M.H., Labrador, A.W., von Rosenvinge, T.T.: 2010, Record-setting cosmic-ray intensities in 2009 and 2010. Astrophys. J. Lett. 723, L1. DOI. ADS. ADSCrossRefGoogle Scholar
  15. Mishev, A.L., Kocharov, L.G., Usoskin, I.G.: 2014, Analysis of the ground level enhancement on 17 May 2012 using data from the global neutron monitor network. J. Geophys. Res. Space Phys. 119, 670. DOI. ADS. ADSCrossRefGoogle Scholar
  16. Moraal, H.: 2013, Cosmic-ray modulation equations. Space Sci. Rev. 176, 299. DOI. ADS. ADSCrossRefGoogle Scholar
  17. Morgado, B., Filipe Maia, D.J., Lanzerotti, L., Gonçalves, P., Patterson, J.D.: 2015, The low energy magnetic spectrometer on Ulysses and ACE response to near relativistic protons. Astron. Astrophys. 577, A61. DOI. ADS. CrossRefGoogle Scholar
  18. Müller-Mellin, R., Böttcher, S., Falenski, J., Rode, E., Duvet, L., Sanderson, T., Butler, B., Johlander, B., Smit, H.: 2008, The solar electron and proton telescope for the STEREO mission. Space Sci. Rev. 136(1), 363. ADSCrossRefGoogle Scholar
  19. Murphy, R.J., Ko, Y.-K.: 2017, Neutron-decay protons from solar flares as seed particles for CME-shock acceleration in the inner heliosphere. Astrophys. J. 846, 53. DOI. ADS. ADSCrossRefGoogle Scholar
  20. Oh, S., Bieber, J.W., Evenson, P., Clem, J., Yi, Y., Kim, Y.: 2013, Record neutron monitor counting rates from galactic cosmic rays. J. Geophys. Res. Space Phys. 118, 5431. DOI. ADS. ADSCrossRefGoogle Scholar
  21. Stone, E.C., Cohen, C.M.S., Cook, W.R., Cummings, A.C., Gauld, B., Kecman, B., Leske, R.A., Mewaldt, R.A., Thayer, M.R., Dougherty, B.L., Grumm, R.L., Milliken, B.D., Radocinski, R.G., Wiedenbeck, M.E., Christian, E.R., Shuman, S., Trexel, H., von Rosenvinge, T.T., Binns, W.R., Crary, D.J., Dowkontt, P., Epstein, J., Hink, P.L., Klarmann, J., Lijowski, M., Olevitch, M.A.: 1998, The cosmic-ray isotope spectrometer for the advanced composition explorer. Space Sci. Rev. 86, 285. DOI. ADS. ADSCrossRefGoogle Scholar
  22. Usoskin, I.G., Alanko-Huotari, K., Kovaltsov, G.A., Mursula, K.: 2005, Heliospheric modulation of cosmic rays: monthly reconstruction for 1951 – 2004. J. Geophys. Res. Space Phys. 110, 12108. DOI. ADS. ADSCrossRefGoogle Scholar
  23. Wraase, S., Heber, B., Böttcher, S., Bucik, R., Dresing, N., Gómez-Herrero, Klassen, A., Müller-Mellin, R.: 2018, Interpretation of increased energetic particle flux measurements by SEPT aboard the STEREO spacecraft and contamination. Astron. Astrophys. 611, A100. DOI. ADS. ADSCrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2018

Authors and Affiliations

  1. 1.Christian-Albrechts-Universität zu KielKielGermany

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