Extreme plasma states in laser-governed vacuum breakdown

Triggering vacuum breakdown at the upcoming laser facilities can provide rapid electron-positron pair production for studies in laboratory astrophysics and fundamental physics. However, the density of the emerging plasma should seemingly stop rising at the relativistic critical density, when the plasma becomes opaque. Here we identify the opportunity of breaking this limit using optimal beam configuration of petawatt-class lasers. Tightly focused laser fields allow plasma generation in a small focal volume much less than ${\lambda}^3$, and creating extreme plasma states in terms of density and produced currents. These states can be regarded as a new object of nonlinear plasma physics. Using 3D QED-PIC simulations we demonstrate the possibility of reaching densities of more than $10^{25}$ cm$^{-3}$, which is an order of magnitude higher than previously expected. Controlling the process via the initial target parameters gives the opportunity to reach the discovered plasma states at the upcoming laser facilities

Extremely high-intensity laser interactions with fundamental quantum systems

The field of laser-matter interaction traditionally deals with the response of atoms, molecules and plasmas to an external light wave. However, the recent sustained technological progress is opening up the possibility of employing intense laser radiation to trigger or substantially influence physical processes beyond atomic-physics energy scales. Available optical laser intensities exceeding 10^{22}\;\text{W/cm^2} can push the fundamental light-electron interaction to the extreme limit where radiation-reaction effects dominate the electron dynamics, can shed light on the structure of the quantum vacuum, and can trigger the creation of particles like electrons, muons and pions and their corresponding antiparticles. Also, novel sources of intense coherent high-energy photons and laser-based particle colliders can pave the way to nuclear quantum optics and may even allow for potential discovery of new particles beyond the Standard Model. These are the main topics of the present article, which is devoted to a review of recent investigations on high-energy processes within the realm of relativistic quantum dynamics, quantum electrodynamics, nuclear and particle physics, occurring in extremely intense laser fields.Comment: 58 pages, 26 figures, version accepted by Reviews of Modern Physic

Extreme laser pulses for possible development of boron fusion power reactors for clean and lasting energy

Extreme laser pulses driving non-equilibrium processes in high density plasmas permit an increase of the fusion of hydrogen with the boron isotope 11 by nine orders of magnitude of the energy gains above the classical values. This is the result of initiating the reaction by non-thermal ultrahigh acceleration of plasma blocks by the nonlinear (ponderomotive) force of the laser field, in addition to the avalanche reaction that has now been experimentally and theoretically manifested. The design of a very compact fusion power reactor is scheduled to produce then environmentally fully clean and inexhaustible generation of energy at profitably low costs. The reaction within a volume of cubic millimetres during a nanosecond can only be used for controlled power generation.Comment: 10 pages, 5 fugure

Laser-Plasma Interactions Enabled by Emerging Technologies

An overview from the past and an outlook for the future of fundamental laser-plasma interactions research enabled by emerging laser systems

Optical Probing of high intensity laser propagation through plasma

This thesis studies the propagation of high intensity lasers through underdense plasmas and the subsequent channel formation. This comprises experimental studies of hole boring mechanism in laser plasma interactions, as well as simulations relevant to these experiments. The experiments described were conducted at the Rutherford Appleton Laboratory (January- April 2009) utilising the Vulcan laser facility. A chapter is dedicated to the characterisation of gas jets used for the channelling experiments. This chapter gives a study of gas flows using different supersonic nozzles and theoretical background that is applicable to laser plasma experiments described later. The major experimental chapter presents, the production of relativistic electron with the interaction of high intensity lasers (1 ps) with under dense plasmas. The experimental results and simulations show that the ponderomotive force of the laser pulse produces an ion channel due to the expulsion of electrons. The interaction of the laser field with the focusing force of the channel leads to significant electron acceleration with energies up to 200 MeV. The final experimental chapter investigates channel creation in deuterium gas jets at varying plasma densities ( 1018 cm−3 - 1020 cm−3), using laser pulses with parameters for the hole-boring phase of the Fast Ignitor scheme of inertial confinment fusion ( τ ~ 30 ps,I = 1018 Wcm−2). The ponderomotive force and relativistic effects cause the laser pulse to self-focus. These effects can guide the laser pulse through the plasma over many Rayleigh lengths. The generation of energetic electrons (~ MeV) was also observed, but with relatively little dependence on density. The experimental data has been also illustrated by simulations, which exhibit good agreement with experimental results for the channel formation

Effect of a strong laser field on e+e−e^+ e^- photoproduction by relativistic nuclei

We study the influence of a strong laser field on the Bethe-Heitler photoproduction process by a relativistic nucleus. The laser field propagates in the same direction as the incoming high-energy photon and it is taken into account exactly in the calculations. Two cases are considered in detail. In the first case, the energy of the incoming photon in the nucleus rest frame is much larger than the electron's rest energy. The presence of the laser field may significantly suppress the photoproduction rate at soon available values of laser parameters. In the second case, the energy of the incoming photon in the rest frame of the nucleus is less than and close to the electron-positron pair production threshold. The presence of the laser field allows for the pair production process and the obtained electron-positron rate is much larger than in the presence of only the laser and the nuclear field. In both cases we have observed a strong dependence of the rate on the mutual polarization of the laser field and of the high-energy photon and the most favorable configuration is with laser field and high-energy photon linearly polarized in the same direction. The effects discussed are in principle measurable with presently available proton accelerators and laser systems.Comment: 21 pages, 4 figure

Laser-Driven Accelerators, Radiations, and Their Applications

Particle accelerators and radiation based on radio-frequency (RF) cavities have significantly contributed to the advancement of science and technology in the most recent century. However, the rising costs and scales for building cutting-edge accelerators act as barriers to accessing these particle and radiation sources. Since the introduction of chirped pulse amplification technology in the 1990s, short-pulse, high-power lasers have enabled the realization of laser-driven accelerations and radiation sources. Laser-driven accelerators and radiation sources could be a viable alternative to providing compact and cost-effective particle and photon sources. An accelerating field in a plasma, driven by intense laser pulses, is typically several orders of magnitude greater than that of RF accelerators, while controlling the plasma media and intense laser pulses is highly demanding. Therefore, numerous efforts have been directed toward developing laser-driven high-quality particle beams and radiation sources with the goal of paving the way for these novel sources to be used in a variety of applications. This Special Issue covers the latest developments in laser-based ion and electron accelerators; laser-plasma radiation sources; advanced targetry and diagnostic systems for laser-driven particle accelerators; particle beam transport solutions for multidisciplinary applications; ionizing radiation dose map determination; and new approaches to laser–plasma nuclear fusion using high-intensity, short laser pulses