The results of Monte-Carlo simulations of electron-positron-photon cascades initiated by slow electrons in circularly polarized fields of ultra-high strength are presented and discussed. Our results confirm previous qualitative estimations [A.M. Fedotov, et al., PRL 105, 080402 (2010)] of the formation of cascades. This sort of cascades has revealed the new property of the restoration of energy and dynamical quantum parameter due to the acceleration of electrons and positrons by the field and may become a dominating feature of laser-matter interactions at ultra-high intensities. Our approach incorporates radiation friction acting on individual electrons and positrons.Comment: 13 pages, 10 figure

Recently, much attention has been attracted to the problem of limitations on the attainable intensity of high power lasers [A. M. Fedotov et al., Phys. Rev. Lett. 105, 080402 (2010)]. The laser energy can be absorbed by electron-positron pair plasma produced from a seed by a strong laser field via the development of the electromagnetic cascades. The numerical model for a self-consistent study of electron-positron pair plasma dynamics is developed. Strong absorption of the laser energy in self-generated overdense electron-positron pair plasma is demonstrated. It is shown that the absorption becomes important for a not extremely high laser intensity I ∼ 10(24)  W/cm(2) achievable in the near future.

It is shown that even a single e- e+ pair created by a superstrong laser field in vacuum would cause development of an avalanchelike QED cascade which rapidly depletes the incoming laser pulse. This confirms Bohr's old conjecture that the electric field of the critical QED strength E(S) = m2c3/eℏ could never be created.

No abstract

Recently much attention has being attracted to the problem of limitations on the attainable intensity of high power lasers [A.M. Fedotov et al. Phys. Rev. Lett. 105, 080402 (2010)]. The laser energy can be absorbed by electron-positron pair plasma produced from a seed by strong laser field via development of the electromagnetic cascades. The numerical model for self-consistent study of electron-positron pair plasma dynamics is developed. Strong absorption of the laser energy in selfgenerated overdense electron-positron pair plasma is demonstrated. It is shown that the absorption becomes important for not extremely high laser intensity I ∼ 10 24 W/cm 2 achievable in the nearest future.PACS numbers: 12.20. Ds,41.75.Jv,42.50.Ct Due to an impressive progress in laser technology, laser pulses with peak intensity of nearly 2 × 10 22 W/cm 2 are now available in the laboratory [1]. When the matter is irradiated by so intense laser pulses ultrarelativistic dense plasma can be produced. Besides of fundamental interest, such plasma is an efficient source of particles and radiation with extreme parameters that opens bright perspectives in development of advanced particle accelerators [2], next generation of radiation sources [3,4], laboratory modeling of astrophysics phenomena [5], etc. Even higher laser intensities can be achieved with the coming large laser facilities like ELI (Extreme Light Infrastructure) [6] or HiPER (High Power laser Energy Research facility) [7]. At such intensity the radiation reaction and quantum electrodynamics (QED) effects become important [8][9][10][11][12][13].One of the QED effects, which has recently attracted much attention, is the electron-positron pair plasma (EPPP) creation in a strong laser field [11,12]. The plasma can be produced via avalanche-like electromagnetic cascades: the seed charged particles are accelerated in the laser field, then they emit energetic photons, the photons by turn decay in the laser field and create electron-positron pairs. The arising electrons and positrons are accelerated in the laser field and produce new generation of the photons and pairs. It is predicted [12] that an essential part of the laser energy is spent on EPPP production and heating. This can limit the attainable intensity of high power lasers. That prediction was derived using simple estimates, therefore self-consistent treatment based on the first principles is needed.The collective dynamics of EPPP in strong laser field is a very complex phenomenon and numerical modeling becomes important to explore EPPP. Up to now the numerical models for collective QED effects in strong laser field have been not self-consistent. One approach in numerical modeling is focused on plasma dynamics and neglects the QED processes like pair production in the laser field. It is typically based on particle-in-cell (PIC) methods and uses equation for particle motion with radiation reaction forces taken into account [13]. The second one is based on Monte Carlo (MC) algorithm for photon emission and electron-positro...