ON SYNCHROTRON-RADIATION ENERGY-LOSSES OF TRAPPED MAGNETOSPHERIC ELECTRONS

Using an energy balance equation it is explicitly demonstrated that sy nchrotron radiation (SR) significantly decelerates several MeV electro ns confined on geomagnetic L-shells below 2 during their radial diffus ive transport into inner magnetosphere. SR losses from the ambient ele ctrons are found to be comparable in importance with Coulomb friction energy losses, a well-known and much modeled cause of energy degradati on in the radiation belts. It may also be true that, under some geophy sical conditions and at some electron energies, the effective electron lifetime due to wave-induced pitch-angle scattering can be shorter th an both the Coulomb and the SR lifetimes. But even when this holds tru e, the effect of the competing SR energy loss process can substantiall y influence the outcome of model computations of the ambient inner zon e electron flux, pitch angle, spatial and energy distributions. We fin d that in the inner radiation zone of the Earth, care must be exercise d to include the simultaneous effects of all three competing electron loss mechanisms. (C) 1998 Elsevier Science Ltd. All rights reserved.