Analysis of capture and surfatron ultrarelativistic acceleration of electrons with initial relativistic energy

The ultrarelativistic acceleration of electrons in space plasma by an electromagnetic wave packet propagating across an external magnetic field is analyzed on the basis of numerical calculations. Electrons capturing conditions by the wave packet, dynamics of their velocity components and particle momentum are discussed depending on the problem initial parameters, including the size of the wave packet. The phase plane structure of the accelerated electrons is considered. The optimal conditions for the realization of ultrarelativistic surfatron acceleration of electrons by spatially localized wave packet are outlined. The occurrence of deviations and variations of the accelerated ultrarelativistic electron from cosmic rays standard power graph is discussed.