New Frontiers of Direct Laser Acceleration in Megatesla Magnetic Fields

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This project examines analytically and using computer simulations a novel regime in which an unprecedented magnetic field, generated in a laser-irradiated solid density target, enhances acceleration of electrons and, as a result, enables emission of copious very energetic photons. Light-matter interactions at ultra-high intensities are the next frontier of the advanced accelerator research with the potential to enable development of novel accelerators and x-ray sources. This regime has the potential to disrupt existing paradigms and advance accelerator science at a fundamental level. The prospect of generating copious quantities of energetic photons in laser-target interactions is of particular interest due to its many possible applications, including photo-nuclear spectroscopy, radiation therapy, and radio surgery. The study is also of fundamental relevance to astrophysics, as it can pave the way to creation of matter and antimatter from light, thus providing valuable insights into the inner workings of the universe. The project will provide essential student training in accelerator science, plasma physics and high performance computing.The novelty of the regime investigated by this project is that the extreme magnetic field couples three key aspects of laser-plasma interactions at high intensities: relativistic transparency, direct laser acceleration, and synchrotron photon emission. The key questions investigated by the project cover fundamental aspects of electron acceleration in Megatesla-level magnetic fields, including energy scaling with plasma and laser pulse parameters, and the mechanism underpinning generation of such a strong laser-driven magnetic field in a plasma. The project specifically examines the interplay between electron acceleration and photon emission. This interplay is the key feature of this regime, because, while the acceleration enhances the photon emission, the photon emission itself has a strong feedback on the microscopic electron motion. In addition to the synchrotron emission, the project also addresses the role of bremsstrahlung. The bremsstrahlung emission can become relevant due to high plasma density, but the presence of the Megatesla magnetic field can have a profound mitigating effect, suppressing photon emission.