Interaction of Relativistic Electrons with Packets of the Electromagnetic Ion Cyclotron Waves of Finite Length and Low Amplitude

Interaction of relativistic electrons with packets of the electromagnetic ion cyclotron waves of finite length and low amplitude in the Earth's radiation belts is analyzed. The variance of the equatorial pitch angle of electrons for wave packets located near the Earth's geomagnetic equator is estimated analytically within the linear approximation. The analytical estimates agree with the results of numerical test-particle simulation. It is demonstrated that reduction in the packet length extends the interaction range to lower energies beyond the range of resonant energies. Such an interaction can result in precipitation of electrons with energies on the order of several hundred kiloelectronvolts into the ionosphere.