Electron ponderomotive acceleration in a vacuum by a short-pulsed
laser of TEM (1, 0) + TEM (0, 1) mode is studied in this paper using a
3-dimensional (3D) particle simulation. It was found that the laser can
trap electrons in transverse and accelerate them with the longitudinal
ponderomotive force at the same time. Through this electron trapping and
acceleration scheme of TEM (1, 0) + TEM (0, 1) mode laser, the electron
bunch is confined well in transverse and compressed remarkably in
longitudinal. Therefore, a high energy, high density, and low emittances
electron bunch is generated. For example, the result shows that for a
laser with intensity of a0 = eE0
/mωc = 10, the laser spot size of
w0 = 15λ, and the laser pulse length of
Lz = 10λ, the maximum energy gain reaches
301 MeV and the average energy 57.7 MeV. The electron bunch transverse
radius is about 350λ and the longitudinal size about 20λ. The
property of this accelerated bunch is improved compared with that
generated by the laser of TEM (0, 0) mode.