High-amplitude plasma wake waves are excited by high-density
relativistic electron bunches (REB) moving in a plasma. The
wake-fields can be used to accelerate charged particles, to
serve as electrostatic wigglers in plasma free-electron lasers
(FEL), and also can find many other applications. The
electromagnetic fields in the region occupied by the bunch control
the dynamics of the bunch itself. This paper presents the results
of 2.5-dimensional numerical simulation of the modulation of
a long REB in a plasma, the excitation of wake-fields by bunches
in a plasma, in particular, in magnetoactive plasma. The previous
one-dimensional study has shown that the density-profile modulation
of a long bunch moving in plasma results in the growth of the
coherent wake-wave amplitude. The bunch modulation occurs at
the plasma frequency. The present study is concerned with the
REB motion, taking into account the plasma and REB nonlinearities.
It is demonstrated that the nonlinear REB/plasma dynamics exerts
primary effect on both the REB self-modulation and the wake-field
excitation by the bunches formed. We have demonstrated that a
multiple excess of the accelerated bunch energy εmax
over the energy of the exciting REB is possible in a magnetoactive
plasma for a certain relationship between the parameters of the
“plasma–bunch–magnetic field” system (owing
to a hybrid volume–surface character of REB-excited wake-fields).
Plasma wake-field excitation by relativistic electron bunches
and charged particle acceleration in the presence of external
magnetic field