Space-time engineering with LASETRON pulses

2007

A signal of 106 14 positrons above background has been observed in collisions of a low-emittance 46.6-GeV electron beam with terawatt pulses from a Nd:glass laser at 527 nm wavelengths in an experiment at the Final Focus Test Beam at SLAC. The positrons are interpreted as arising from a two-step process in which laser photons are backscattered to GeV energies by the electron beam, followed by a collision between the high-energy photon and several laser photons to produce an electron-positron pair. These results are the rst laboratory evidence for inelastic light-by-light scattering involving only real photons. Supported by DOE Grant DE-FG02-91ER40671. y See Acknowledgments. z c 1997 by Kirk T. McDonald.

Journal of Experimental and Theoretical Physics, 2010

The space-velocity distribution of electrons propagating in vacuum can be deformed by the pon deromotive potential produced by high intensity femtosecond laser pulses, which makes it possible to subse quently separate such electrons from the initial beam. It is shown that optical modification of electron beams with kinetic energies on the order of 100 eV by femtosecond laser radiation with an intensity from 10 14 to 10 18 W/cm 2 makes it possible to form electron beams with a duration on the order of 50-100 fs. Examples of optical control over the shape of electron beams, based on deflection, reflection, focusing, and splitting of electron beams, are considered.

Physics Reports, 2006

... In recent years it has become possible to generate femtosecond laser pulses at relativistic ... Further in 2000, the physics and technology of ultrashort-pulse lasers was the ... in the quantum-mechanical study of the relativistic effects associated with high-intensity laser interactions ...

Journal of Physics A: Mathematical and Theoretical

We discuss the use of a class of exact finite energy solutions to the vacuum source-free Maxwell equations as models for multi-and single cycle laser pulses in classical interaction with relativistic charged point particles. These compact solutions are classified in terms of their chiral content and their influence on particular charge configurations in space. The results of such classical interactions motivate a phenomenological quantum description of a propagating laser pulse in a medium in terms of an effective quantum Hamiltonian.

Physics Letters B, 2011

A detection scheme for characterizing high-energy $\gamma$-ray pulses down to the zeptosecond timescale is proposed. In contrast to existing attosecond metrology techniques, our method is not limited by atomic shell physics and therefore capable of breaking the MeV photon energy and attosecond time-scale barriers. It is inspired by attosecond streak imaging, but builds upon the high-energy process of electron-positron pair production in vacuum through the collision of a test pulse with an intense laser pulse. We discuss necessary conditions to render the scheme feasible in the upcoming Extreme Light Infrastructure laser facility.

Physics of Plasmas, 2000

In our Petawatt laser experiments several hundred joules of 1 µm laser light in 0.5-5.0 ps pulses with intensities up to 3x10 20 Wcm -2 were incident on solid targets producing a strongly relativistic interaction. The energy content, spectra, and angular patterns of the photon, electron, and ion radiations were diagnosed in a number of ways, including several novel (to laser physics) nuclear activation techniques. From the beamed bremsstrahlung we infer that about 40-50% of the laser energy is converted to broadly beamed hot electrons. Their direction centroid varies from shot to shot, but the beam has a consistent width. Extraordinarily luminous ion beams almost precisely normal to the rear of various targets are seen -up to 3x10 13 protons with kT ion ~ several MeV representing ~6% of the laser energy.

Applied Physics, 1980

Methods are described for gathering positrons from an extended region and causing them to impact upon a target surface within a small time interval. The most optimistic of these proposed schemes suggests that one should be able to produce ~ 10-9s positron pulses with peak intensities of ~ 1011 s-1 starting with a ~200 m Ci S SCo/3 + source. These pulses should be useful for studying time-dependent interactions of positrons at surfaces.

Physics of Plasmas

High-energy short-pulse lasers are pushing the limits of plasma-based particle acceleration, x-ray generation, and high-harmonic generation by creating strong electromagnetic fields at the laser focus where electrons are being accelerated to relativistic velocities. Understanding the relativistic electron dynamics is key for an accurate interpretation of measurements. We present a unified and self-consistent modeling approach in quantitative agreement with measurements and differing trends across multiple target types acquired from two separate laser systems, which differ only in their nanosecond to picosecond-scale rising edge. Insights from high-fidelity modeling of laser-plasma interaction demonstrate that the ps-scale, orders of magnitude weaker rising edge of the main pulse measurably alters target evolution and relativistic electron generation compared to idealized pulse shapes. This can lead for instance to the experimentally observed difference between 45 MeV and 75 MeV maxi...

Plasma Physics and Controlled Fusion, 2016

The generation of high-quality relativistic positron beams is a central area of research in experimental physics, due to their potential relevance in a wide range of scientific and engineering areas, ranging from fundamental science to practical applications. There is now growing interest in developing hybrid machines that will combine plasma-based acceleration techniques with more conventional radio-frequency accelerators, in order to minimise the size and cost of these machines. Here we report on recent experiments on laser-driven generation of high-quality positron beams using a relatively low energy and potentially table-top laser system. The results obtained indicate that current technology allows to create, in a compact setup, positron beams suitable for injection in radio-frequency accelerators.

Tech. Phys. Lett., 2005

The interactions of relativistic electrons with laser radiation are classified in terms of three Lorentz-invariant quantities, which can be determined using the laser radiation parameters and the electron energy. The proposed classification covers the entire range of electron energies and laser radiation intensities presently in use, with allowance for quantum effects and nonlinear processes of higher harmonic generation.