Interactions at extremely high electromagnetic energy densities and QED processes in supercritical fields

• Applicant: Professor Dr. Alexander Pukhov
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 430078384

The next generation of laser facilities is now under construction around the globe, including the European project ELI, the POLARIS laser in Dresden (Germany) and the XCELS laser in Nizhny Novgorod (Russia). At the same time, multi-GeV linear electron colliders are in operation at DESY (Germany) and at the Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC (USA). It is planned to combine both of them with powerful femtosecond optical lasers.Spectacular progress both in the laser technology and in conventional as well as in plasma-based methods for particle acceleration opens unique opportunities for experimental studies of Intense Field Quantum Electrodynamics (IFQED) effects, including those yet almost unexplored, such as high-order (in terms of the fine structure constant) radiative corrections.When the field strength in a proper reference frame of an ultrarelativistic particle exceeds the Schwinger value by a factor up to 1000, IFQED radiative corrections may become significant. In this context of exceptional interest is the recently proposed medium-term progressive upgrade of the FACET-II facility. It aims at the creation of an extreme beam collider with 100 GeV lepton beams carrying Mega-Ampere currents and focused to nanometer scale. Thus for the first time the bunch density at the interaction point will exceed the Compton density. We will face a novel regime when extremely high energy leptons interact with extreme fields and energy densities. A theoretical description is currently missing here.Our proposal aims at the development of both theory and modeling of such supercritical IFQED regimes. We will explore (i) the interaction of counter-propagating high-current lepton beams and (ii) the interaction of extremely short and intense electromagnetic pulses with ultrarelativistic electrons. In both setups the dynamic quantum parameter of the particles is assumed much higher than 1. Moreover, it can be so high (up to 1000) that high-order IFQED radiative corrections have to be taken into account (highly supercritical IFQED regime). We propose to calculate the probabilities of the basic IFQED processes in this regime, for which the existing theoretical approaches must be reconsidered substantially.The obtained analytical results will then be implemented in our QED-PIC codes VLPL and QUILL. The modified codes will be used to simulate the laser-beam and beam-beam interactions in a highly supercritical regime, relevant for the future high-current lepton colliders and extreme intensity laser pulses.Our results may be of substantial interest for astrophysics, where the description of certain phenomena requires the postulation of supercritical magnetic fields and the interaction of ultrarelativistic jets. The proposed workplan at the junction of IFQED and modeling of the nonlinear processes in ultrarelativistic plasmas is unique and corresponds to (in certain aspects even surpasses) the advanced international level in the field

• DFG Programme: Research Grants
• International Connection: Russia
• Partner Organisation: Russian Foundation for Basic Research, until 3/2022
• Cooperation Partner: Professor Dr. Igor Kostyukov, until 3/2022