Electron-positron pair production by photons in nonuniform strong fields

Optimizing electron-positron pair production on kilojoule-class high-intensity lasers for the purpose of pair-plasma creation

Expressions for the yield of electron-positron pairs, their energy spectra, and production rates have been obtained in the interaction of multi-kJ pulses of high-intensity laser light interacting with solid targets. The Bethe-Heitler conversion of hard x-ray bremsstrahlung [D. A. Gryaznykh, Y. Z. Kandiev, and V. A. Lykov, JETP Lett. 67, 257 (1998); K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505 (2002)] is shown to dominate over direct production (trident process) [E. P. Liang, S. C. Wilks, and M. Tabak, Phys. Rev. Lett. 81, 4887 (1998)]. The yields and production rates have been optimized as a function of incident laser intensity by the choice of target material and dimensions, indicating that up to 5 x 10 (11) pairs can be produced on the OMEGA EP laser system [L. J. Waxer, Opt. Photonics News 16, 30 (2005)]. The corresponding production rates are high enough to make possible the creation of a pair plasma.

Solitary phase-space holes in pair plasmas

We present theoretical and computer simulation studies of the formation and dynamics of solitary phase-space holes in pair plasmas, which can be applied to both electron-positron plasmas and to plasmas containing positively and negatively charged macro-ions or macro-particulates (charged dust grains). We apply our numerical treatment to the parameters used in a recent series of experiments in a pair ion plasma whose constituents are negatively and positively charged fullerene carbon nanotubes. New experiments should be conducted to confirm our theoretical and numerical predictions.