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, Ivanov for fruitful discussions, E. Lefebvre for providing the PIC code CALDER and R. Nuter for modifying this code to include the CE phase parameter. The 2D PIC calculations were performed using the computing resources of the, Acknowledgement: The authors would like to thank M

, (GENCI), under project number 2011-056057, and those of the "Centre de Calcul Recherche et, Calcul Intensif

. Technologie, A.B. acknowledges financial support from the RTRA -Triangle de la Physique and F.Q. from the European Research Council, 2004.
URL : https://hal.archives-ouvertes.fr/hal-02855753

, Authors contributions: The experimental setup was designed by A.B. and R.L-M., the experiments were carried out by A.B. and A.M. The theoretical work was done by