Electron dynamics in an elliptical bubble regime

In this paper, the dynamics of the electron in an elliptical bubble regime is investigated. In this regime, a high intensity laser pulse in a plasma creates an electron cavity called the blow-out (bubble or cavitation) regime which is usually considered to be in a spherical shape at rest. Through balancing the ponderomotive potential of a non-plane laser pulse and bubble electrostatic potential, the shape of the bubble is analyzed to be elliptical in contrast to most available theories which indicate the spherical bubble. Thus, the present model introduces a different dynamics for the electron compared with the spherical one. The longitudinal electric field experienced by the electron and also the electron energy gain in the elliptical model is investigated to be more than that in the spherical model. Moreover, it is found that the shape of the bubble will influence the electron trapping range so that the electron is bounded more in the spherical bubble. As a result, it is crucially important to take the shape of the bubble influence on the electron acceleration process into account. The results indicate that the distribution of the electromagnetic fields inside the bubble in the ellipse model is more close to particle-in-cell simulation compared to the spherical one [Kostyukov et al., Phys. Plasmas 11(11), 5256 (2004)].