The advent of ultraintense laser pulses generated by the technique of chirped pulse amplification (CPA) along with the development of high-fluence laser materials has opened up an entirely new field of optics. The electromagnetic field intensities produced by these techniques, in excess of ${10}^{18}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$, lead to relativistic electron motion in the laser field. The CPA method is reviewed and the future growth of laser technique is discussed, including the prospect of generating the ultimate power of a zettawatt. A number of consequences of relativistic-strength optical fields are surveyed. In contrast to the nonrelativistic regime, these laser fields are capable of moving matter more effectively, including motion in the direction of laser propagation. One of the consequences of this is wakefield generation, a relativistic version of optical rectification, in which longitudinal field effects could be as large as the transverse ones. In addition to this, other effects may occur, including relativistic focusing, relativistic transparency, nonlinear modulation and multiple harmonic generation, and strong coupling to matter and other fields (such as high-frequency radiation). A proper utilization of these phenomena and effects leads to the new technology of relativistic engineering, in which light-matter interactions in the relativistic regime drives the development of laser-driven accelerator science. A number of significant applications are reviewed, including the fast ignition of an inertially confined fusion target by short-pulsed laser energy and potential sources of energetic particles (electrons, protons, other ions, positrons, pions, etc.). The coupling of an intense laser field to matter also has implications for the study of the highest energies in astrophysics, such as ultrahigh-energy cosmic rays, with energies in excess of ${10}^{20}\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The laser fields can be so intense as to make the accelerating field large enough for general relativistic effects (via the equivalence principle) to be examined in the laboratory. It will also enable one to access the nonlinear regime of quantum electrodynamics, where the effects of radiative damping are no longer negligible. Furthermore, when the fields are close to the Schwinger value, the vacuum can behave like a nonlinear medium in much the same way as ordinary dielectric matter expanded to laser radiation in the early days of laser research.

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Optics in the relativistic regime

http://absimage.aps.org/image/DAMOP12/MWS_DAMOP12-2012-000066.pdf

Optics in the Relativistic Regime

Computer Solution of Linear Algebraic Systems. By G. Forsythe and C. B. Moler. Pp. xi, 148. 1967. (Prentice-Hall.)

Non-thermal plasma processing for environmental protection: decomposition of dilute VOCs in air

Cluster-surface interaction: From soft landing to implantation

The generation of a quasi-monoenergetic electron beam in laser-driven plasma acceleration is reported. A monoenergetic electron beam with an energy of 7 MeV was emitted from a high-density plasma (electron density >1020cm−3) produced by a 2 TW 50 fs laser pulse. The divergence of the monoenergetic beam was ±1.2°. The first Stokes satellite peak of stimulated forward Raman scattering was observed in the spectrum of the light transmitted through the plasma. The plasma wave was excited in the region of which electron density was around 1.3×1020cm−3. The acceleration length was estimated to be 500μm from the length of the side-scattered light image. It is considered that the monoenergetic beam generation is due to the matching of the acceleration length to the dephasing length determined by the velocity difference between the accelerated electrons and the plasma wave.

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Demonstration of quasi-monoenergetic electron-beam generation in laser-driven plasma acceleration

Preliminary results of the experimental determination of the particle loss aperture sizes of the spindle cusp magnetic bottle for laser‐produced high‐beta deuterium plasmas are presented. The fully ionized dense plasma (with maximum density ∼1016 cm−3 and ion energy ∼200 V) is produced at the null‐field center of the magnetic bottle, from a freely falling isolated deuterium ice pellet by a focused giant laser pulse. In preparation, the free expansion of laser‐produced plasma has been studied experimentally, and the results indicate that the plasmas produced can maintain the fully ionized condition with prescribed plasma parameters until it expands to a certain prescribed volume if the combination of the physical parameters is properly chosen by considering the electron‐ion recombination as one of the important factors. The experimental results of cusp confinement for the plasma thus produced suggest that the loss aperture size of the ring cusp is much smaller than the local ion gyroradius, in sharp contra...

Cusp confinement of high‐beta plasmas produced by a laser pulse from a freely‐falling deuterium ice pellet

We have demonstrated the acceleration of a monoenergetic electron beam by a laser-produced wakefield. Experiments wereperformedbyfocusing2-TWlaserpulsesof50fsonsupersonicgas-jettargets.Thefocusedintensitywas5! 10 18 W0cm 2 ~a0" 1.5!. At an electron density of 1.5 ! 10 20 cm # 3 , the clear monoenergetic electron beam from the plasma wasobtainedat7to15MeV.TheStokessatellitepeakintheforwardscatteringexplainedtheenergyspectraofelectrons at various plasma densities well.Although the wakefield propagated 500 microns, which was far beyond the dephasing length, monoenergetic electron beams were obtained.

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Monoenergetic electron beam generation from a laser-plasma accelerator

A simple direct acceleration model is proposed, taking into account the stochastic phase disturbance of the coherent driving laser fields. A relativistic single particle simulation shows that plasma electrons are efficiently accelerated far above the ponderomotive energy. The energy and momentum distributions of the accelerated electrons are derived to examine the effects of the self-generated magnetic field on the characteristics of the electron beams. In addition to the beam collimation effect, the magnetic field is found to further enhance the electron acceleration, resulting in the generation of ultrahigh energy electrons.

/pdf/direct-electron-acceleration-by-stochastic-laser-fields-in-2epgoaossd.pdf

Direct electron acceleration by stochastic laser fields in the presence of self-generated magnetic fields.

http://www.hino.meisei-u.ac.jp/ee/tanimoto/CPL_LIF.pdf

Mitsumori Tanimoto

Papers

Demonstration of quasi-monoenergetic electron-beam generation in laser-driven plasma acceleration

Cusp confinement of high‐beta plasmas produced by a laser pulse from a freely‐falling deuterium ice pellet

Monoenergetic electron beam generation from a laser-plasma accelerator

Direct electron acceleration by stochastic laser fields in the presence of self-generated magnetic fields.

Removal processes of nitric oxide along positive streamers observed by laser-induced fluorescence imaging spectroscopy