Vacuum instability in a strong laser field

Laser systems with radiation intensity exceeding 1024 W/cm2 will be available around the world in the near future. Such intensity level opens up an opportunity of testing QED fundamentals, laboratory study of QED vacuum structure and development of novel gamma-ray sources.

IAP researchers headed by I. Yu. Kostyukov have demonstrated that at such intensities avalanche-like electron-positron pair production can occur in vacuum due to the development of QED cascade, by analogy with the electron avalanche of gas discharge in the electric field. A seed charged particle is accelerated in the laser field and emits a gamma quantum which is then split in the strong field into an electron-positron pair. The resulting pair is also accelerated and produces the next generation of gamma-quanta and electron-positron pairs. The resulting medium with high energy density efficiently absorbs laser light, which may be the fundamental mechanism that limits the intensity of electromagnetic radiation achievable in laboratory conditions.

Research on this topic in IAP RAS has resulted in the development of an analytical model of QED cascading in a rotating electric field; in the first ab initio demonstration of laser field absorption due to self-generated electron-positron plasma with full-scale 3D numerical simulations, and in the proposal of an intense gamma-rays source based on QED cascading.

Laser intensity in case of two colliding linearly polarized laser pulses at the beginning (top left) and 70 fs after cascade development (top right);
normalized density of electrons and positrons (bottom left) and normalized density of hard photons (bottom right) 70 fs after cascade development