C Rechatin1, J
Faure1, A
Lifschitz1,2, X
Davoine3, E
Lefebvre3 and V
Malka1,4
1 Laboratoire
d'Optique Appliquée, ENSTA, CNRS, Ecole Polytechnique, UMR
7639, 91761 Palaiseau, France
2 Laboratoire
de Physique des Gaz et des Plasmas, CNRS, UMR 8578,
Université Paris XI, Bâtiment 210, 91405 Orsay cedex, France
3 Département
de Physique Théorique et Appliquée, CEA, DAM Ile-de-France,
BP 12, 91680 Bruyères-le-Châtel, France
4 Author
to whom any correspondence should be addressed.
E-mail: victor.malka@ensta.fr
Abstract. The
interaction of two laser pulses in an underdense plasma
has been proven to be able to inject electrons into
plasma waves, thus providing a stable and tunable source
of electrons. Whereas previous works focused on the 'beatwave'
injection scheme in which two lasers with the same
polarization collide in a plasma, this present paper
studies the effect of polarization and more specifically
the interaction of two colliding cross-polarized laser
pulses. It is shown both theoretically and
experimentally that electrons can also be preaccelerated
and injected by the stochastic heating occurring at the
collision of two cross-polarized lasers and thus, a new
regime of optical injection is demonstrated. It is found
that injection with cross-polarized lasers occurs at
higher laser intensities.