Electron dynamics controlled via self-interaction

The dynamics of an electron in a strong laser field can be significantly altered by radiation reaction. This usually results in a strongly damped motion, with the electron losing a large fraction of its initial energy. Here we show that the electron dynamics in a bichromatic laser pulse can be indirectly controlled by a comparatively small radiation reaction force through its interplay with the Lorentz force. By changing the relative phase between the two frequency components of the bichromatic laser field, an ultrarelativistic electron bunch colliding head-on with the laser pulse can be deflected in a controlled way, with the deflection angle being independent of the initial electron energy. The effect is predicted to be observable with laser powers and intensities close to those of current state-of-the-art petawatt laser systems.

Figure 1

Electron density distribution $n_e(p_z,p_x)$ as a function of the longitudinal $p_z$ and transverse $p_x$ momentum after the interaction of 400 electrons with a bichromatic laser pulse. Panel (a): $cos\left({\theta }_2\right)=0$ without RR. Panel (b): $cos\left({\theta }_2\right)=0$ with RR. Panel (c): $cos\left({\theta }_2\right)=1$ without RR. Panel (d): $cos\left({\theta }_2\right)=1$ with RR. See the text for further numerical details.

Figure 2

Trajectory of an electron colliding head-on with a bichromatic laser pulse without (blue dashed line) and with (red solid line) RR force included. The corresponding plane-wave result with RR (green dotted line) is also reported for comparison. In all cases ${\theta }_1=0$. Panel (a): $cos\left({\theta }_2\right)=-1/\sqrt{2}$. Panel (b): $cos\left({\theta }_2\right)=0$. Panel (c): $cos\left({\theta }_2\right)=1/\sqrt{2}$. Panel (d): $cos\left({\theta }_2\right)=1$. See the text for further numerical details.