Antiprotons confined in the earth’s inner magnetosphere

The possible existence of noticeable fluxes of antiparticles in the Earth magnetosphere is considered theoretically in this article. These antiparticles (antiprotons in this paper) that are confined by geomagnetic field at the altitudes of several hundred kilometers are predominantly not of immediate extraterrestrial origin, but rather are the products of nuclear reactions of the high energy primary cosmic rays (CR) with constituents of the terrestrial atmosphere. Direct extraterrestrial antiprotons impinging upon the Earth’s magnetosphere are themselves also secondary in origin, i.e. they are born in nuclear reactions of the same CR passing through 5–7 g/cm2 of interstellar matter. These exhibit lower fluxes compared to the magnetospheric antiprotons that are born at a pass length of hundreds g/cm2 in the residual Earth atmosphere. Such locally generated antiprotons can be confined by the magnetic field of the Earth (or equivalently by another planet) and so accumulated in the magnetosphere. We here present the results of numerical simulation of antiproton fluxes in the energy range from 10 MeV to several GeV produced by CR in the Earth’s atmosphere at altitudes of about 1000 km, and we compare this to antiprotons born in interstellar matter. The estimates presented herein show a significant (up to two orders of magnitude) excess of magnetospheric antiproton fluxes over those formed in the interstellar media at energies <1 to 2 GeV.