Specific features of the distribution of protons at small altitudes in near-equatorial latitudes according to data of satellite experiments. I. Energy spectrum

The spectra of protons with energies from 10 keV to 1 MeV as measured in experiments conducted at satellites and the MIR orbital station are presented. These data were obtained in the area of the geomagnetic equator at L < 1.15 and at altitudes up to 1000 km. The proton spectrum was determined during periods of geomagnetic perturbations and quite periods. These spectra were approximated using a kappa-function. The proton spectra in the near-equatorial area and in the ring current are compared. The proton’s life time in the near-equatorial area is estimated, taking into account charge exchange and Coulomb scattering. It is confirmed that the ring current is a main source of protons in the near-equatorial area at low altitudes.