Possibility of Prolific Pair Production with High-Power Lasers

Prolific electron-positron pair production is possible at laser intensities approaching ${10}^{24}\mathrm{W}{\mathrm{cm}}^{-2}$ at a wavelength of $1\mu \mathrm{m}$. An analysis of electron trajectories and interactions at the nodes ($B=0$) of two counterpropagating, circularly polarized laser beams shows that a cascade of $\gamma$ rays and pairs develops. The geometry is generalized qualitatively to linear polarization and laser beams incident on a solid target.

Figure 1

The parameters $\eta$ and $\chi$—see Eqs. (1, 7)—controlling the importance of electromagnetic conversion by the accelerated electron and its curvature photon, respectively, as a function of laser intensity, for a laser wavelength of $1\mu \mathrm{m}$. Also plotted are the optical depth $\tau$ of the curvature photon across one wavelength, the number $N_{\pm }$ of pairs produced per electron in one laser period by both this process and by that of pair production by the trident process—labeled ${\tau }_{\mathrm{tr}}$, and the number $N_{\gamma }$ of curvature radiation photons produced per electron per laser period.