Skip to main content
  • Article
  • Published:

Trapped positron flux formation in the innermost magnetosphere of the Earth


The possible existence of a positron radiation belt in the inner magnetosphere of the Earth, its space location, flux, energy distribution and the ratio of e+/e fluxes is considered. The source of the positrons/electrons is assumed to be the decay of charged pions (π - μ - e decay chain) produced, in the nuclear interactions between protons and the neutral constituents of the atmosphere. The production of excess positron fluxes over electron ones through this process is examined for two different proton populations and their atmospheric interactions in the altitude range of 80 to 1000 km. Monte Carlo simulations of intranuclear cascade process through SHIELD code was utilized to simulate these interactions. Considering the trapped proton fluxes in the inner magnetosphere as a source, the simulations for interactions in rarified atmosphere shows excess of positrons over electrons with ratios above 2 for proton energies below 2.5 GeV. Although, protons above this energy do not produce excess of positrons compared to electrons in atmospheric interactions, we assumed the primary cosmic rays with the energy greater than 8–10 GeV also as a source for these interactions, and utilizing the east-west asymmetry in the arrival directions of these primary cosmic rays combined with the exponential nature of the atmosphere density we also obtained an excess of positrons over electrons escaping from the atmosphere to the altitudes of satellite orbits. A comparison is attempted with the recent data of AMS experiment on board the space shuttle.


  • AP8,, 1996.

  • Barashenkov, V. S. and V. D. Toneev, Interaction of Particles and Atomic Nuclei of High and Superhigh Energies with Nuclei, Atomizdat, Moscow, Russia, 812 pp., 1972.

    Google Scholar 

  • Basilova, R. N., A. A. Gusev, G. I. Pugacheva, and A. F. Titenkov, High energy trapped electrons in the inner radiation belt, Geom. Aeronom., 22, 671–673, 1982.

    Google Scholar 

  • Chen, J., T. G. Guzik, Y. Sang, and J. P. Wefel, Energetic helium particles trapped in the magnetosphere, Geophys. Res. Lett., 21, 1583–1586, 1994.

    Article  Google Scholar 

  • Dementyev, A. V. and N. M. Sobolevsky, SHIELD—universal Monte Carlo hadron transport code: scope and applications, Radiation Measurements, 30, 553–562, 1999.

    Article  Google Scholar 

  • Freden, S. C. and R. S. White, Particle fluxes in the inner radiation belt, J. Geophys. Res., 65(5), 1377–1383, 1960.

    Article  Google Scholar 

  • Galper, A. M., V. M. Grachev, V. V. Dmitrenko, et al., High energy electrons in the radiation belt of the Earth, 18 Int. Cosmic Ray Conference, Bangalore, India, MG.10-33, 497–500, 1983.

  • Guinzburg, V. L., Astrophysics of Cosmic Rays, pp. 358, Nauka, Moscow, Russia, 1984 (in Russian).

  • Gusev, A. A., I. M. Martin, G. I. Pugacheva, A. Turtelli, Jr., W. N. Spjeldvik, Energetic positron population in the inner zone, Il Nuovo Cimento, Sect. C, 19, 461–465, 1996.

    Article  Google Scholar 

  • Gusev, A. A., U. B. Jayanthi, G. I. Pugacheva, and W. N. Spjeldvik, Nuclear reactions on rarest atmosphere as a source of magnetospheric positron radiation belt, J. Geophys. Res., 106(A11), 26111–26115, 2001.

    Article  Google Scholar 

  • Hedin, A. E., Extension of the MSIS thermospheric model into the middle and lower atmosphere, J. Geophys. Res., 96, 1159–1168, 1991.

    Article  Google Scholar 

  • Machner, H. and J. Hidenbauer, Meson production close to threshold, Journal of Physics G: Nuclear and Particle Physics, 25(10), 231–271, 1999.

    Article  Google Scholar 

  • Pugacheva, G. I., W. N. Spjeldvik, A. A. Gusev, and I. M. Martin, On the natural energetic positron population in the inner zone of the Earth, J. Atmos. Solar-Terr Phys., 59, 363–369, 1997.

    Article  Google Scholar 

  • Pugacheva, G. I., W. Gonzalez, A. A. Gusev, U. B. Jayanthi, I. M. Martin, D. Boscher, S. Bourdarier, and W. N. Spjeldvik, Numerical simulation of steady state proton, positron, isotope ion radiation belts and of a sudden creation of transient helium radiation belt during geomagnetic storms, ISEC2001 Radiation Belt Science and Technology, July 23–27, 2001, Queenstown, New Zealand, [], 2001.

  • Selesnick, R. S. and R. A. Mewaldt, Atmospheric production of radiation belt light isotopes, J. Geophys. Res., 101(A10), 19745–19759, 1996.

    Article  Google Scholar 

  • Spjeldvik, W. N., G. I. Pugacheva, A. A. Gusev, I. M. Martin, and N. M. Sobolevsky, Sources of inner Radiation Zone Energetic Helium Ions: cross-field transport versus in-situ nuclear reactions, Adv. SpaceRes., 21, 1675–1678, 1998a.

    Article  Google Scholar 

  • Spjeldvik, W. N., G. I. Pugacheva, A. A. Gusev, I. M. Martin, and N. M. Sobolevsky, Hydrogen and helium isotope inner radiation belts in the Earth’s magnetosphere, Annales Geophysicae, 16, 931–939, 1998b.

    Article  Google Scholar 

  • The AMS collaboration, Protons in near Earth orbit, Phys. Lett. B, 472, 215–226, 2000a.

    Article  Google Scholar 

  • The AMS collaboration, Leptons in near Earth’s orbit, Phys. Lett. B, 484, 10–17, 2000b.

    Article  Google Scholar 

  • Voronov, S. A., A. M. Galper, V. G. Kirillov-Ugryumov, S. V. Koldashev, and A. V. Popov, High energy electrons and positrons in the Earth’s radiation belt, Geom. and Aeronom., 27(3), 424–427, 1987.

    Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to A. A. Gusev.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Gusev, A.A., Jayanthi, U.B., Pugacheva, G.I. et al. Trapped positron flux formation in the innermost magnetosphere of the Earth. Earth Planet Sp 54, 707–714 (2002).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: