The outer boundary of radiation belts by the data of the ''Kosmos-426'' satellite

Examined are the variations of the position of the external boundary of the radiation belts in magnetically calm periods as a function of the geomagnetic time MLT, orientation of the interplanetary magnetic field (IMF) and angle of slope of the geomagnetic dipole with respect to the Sun-Earth line. Experimental data have been obtained with the aid of the instrument which detected electrons with energies E > 20 keV on the ''Kosmos-426'' satellite during the period from 04.06.1971 to 3.01.1972. The effect of the angle of slope of the geomagnetic axis is maximum in after-midnight hours of MLT in the hemisphere with summer solstice. During the period of the northern orientation of the vertical component of IMF in almost all the MLT intervals, with the exception of after-midnight hours (2 to 8 hours MLT), the boundary is located at greater latitudes than in the southern orientation. The boundary correlates with the magnitude of the southern component of the IMF and does not correlate with the magnitude of the northern component of IMF