Speaker
Description
Plasmas immersed in ultra-intense electromagnetic fields radiate through QED channels high-energy photons which can decay into pairs. These pairs, if created in sufficient amounts, can significantly impact the background field. This is especially true in the context of QED avalanches created by intense lasers, where the exponentially growing density will eventually reach a critical value whereupon the laser field starts to be depleted [1-2].
In this work, we propose a model to address the response of the pair plasma on the background field in the weak field limit ($\chi \ll 1$), where the effect of radiation can be treated with classical friction. Starting from Ampère’s equation and the equations of motions of charges, we obtain a system of differential equations on particle momenta and the total electric field. The analytical model is compared with Particle-In-Cell simulations and is found to be in good agreement.
Furthermore, using dynamical systems analysis tools, we can provide analytical predictions about the asymptotic response of the plasma. For instance, we can give the necessary conditions for significant screening of in constant and oscillating external field, which is consistent with previous numerical works [1-2].
[1] Grismayer, T., et al. (2016). Physics of Plasmas, 23(5), 056706
[2] Nerush, E. N., et al. (2011) Phys. Rev. Lett. 106, 035001
