  The nonlinear evolution of the Weibel instability driven by the anisotropy of
the electron distribution function in a collisionless plasma is investigated in
a spatially one-dimensional configuration with a Vlasov code in a
two-dimensional velocity space. It is found that the electromagnetic fields
generated by this instability cause a strong deformation of the electron
distribution function in phase space, corresponding to highly filamented
magnetic vortices. Eventually, these deformations lead to the generation of
short wavelength Langmuir modes that form highly localized electrostatic
structures corresponding to jumps of the electrostatic potential.
