LASER-BASED ACCELERATOR FOR INTERROGATION OF REMOTE CONTAINERS

A method and apparatus for generating high-energy beams of electrons or x-rays through laser wakefield acceleration to remotely examine containers is disclosed. By scanning the beam of electrons or x-rays across a container, an inspector can remotely determine whether the containers contain items of interest, such as special nuclear materials, without having to manually inspect the contents of the container. The invention can be compact enough to be portable, which provides for the flexibility to examine a variety of different containers under a variety of different conditions

Laser-Produced Coherent X-Ray Sources

We study the generation of x-rays from the interaction of relativistic electrons with ultra-intense laser pulse either directly or via laser generated ion channels. The laser pulse acts as the accelerator and wiggler leading to an all-optical synchrotron-like x-ray source. The mm sized accelerator and micron-sized wiggler leads to a compact source of high brightness, ultrafast x-rays with applications in relativistic nonlinear optics, ultrafast chemistry, biology, inner-shell electronic processes and phase transitions

Cold relativistic wavebreaking threshold of two-dimensional plasma waves

The two-dimensional wave-breaking of relativistic plasma waves driven by a ultrashort high-power lasers, is described within a framework of cold 2-D fluid theory. It is shown that the transverse nonlinearity of the plasma wave results in temporally increasing transverse plasma oscillation in the wake of the laser pulse, inevitably inducing wave-breaking below the 1-D threshold. A condition for wave-breaking is obtained and evaluated. A preformed density channel is found to partially cancel the effect and increase the length of wakefield that survives before wavebreaking occurs. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87717/2/404_1.pd

All-Optical Laser-Wakefield Electron Injector

Demonstrated the principle of optical control of laser accelerators, namely, that one laser pulse could modify the properties (e.g., emittance and electron number) of an electron beam accelerated by a separate but synchronized laser pulse. Another recent highlight was that, using our new 30-fs 10-TW laser system, we accelerated with a laser accelerator an electron beam with a record low divergence (0.2 degrees). This is more than 100 times lower than the 30-degree divergence that was reported recently by a French group using a laser with similar parameters

Resonant laser‐plasma electron acceleration

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87302/2/65_1.pd

Electron Injection by Dephasing Electrons with Laser Fields

The authors seek to review injection concepts for plasma based acceleration. It is shown that regardless of injection mechanism, resultant beams will be similar due to wave structure. Also, most schemes employ the same basic processes, namely the dephasing of electrons by laser fields, and can thus be analyzed with similar approaches

ULTRA-SHORT WAVELENGTH X-RAY SYSTEM

A method and apparatus to generate a beam of coherent light including X-rays or XUV by colliding a high-intensity laser pulse with an electron beam that is accelerated by a Syn chronized laser pulse. Applications include X-ray and EUV lithography, protein Structural analysis, plasma diagnostics, X-ray diffraction, crack analysis, non-destructive testing, Surface Science and ultrafast Science

Harmonic Generation by an Intense Laser Pulse in Neutral and Ionized Gases

Reported are the results of a harmonic generation experiment in a simple gas (hydrogen) using 1-ps, 1-pm laser pulses with a range of intensities extending from below to far above the laser ionization saturation threshold. The scaling with intensity above saturation of the third harmonic generated by a single laser-pulse in a filled gas cell is observed to not fit with a simple model that takes into consideration volume ionization effects alone. In another experiment, a pump-probe type, an upper limit on the conversion efficiency of third harmonic generation in a preformed plasma is determined. It is found to be in agreement with the efficiency predicted by a relativistic harmonic generation theory

TOPICAL REVIEW: Relativistic laser–plasma interactions

By focusing petawatt peak power laser light to intensities up to 1021 W cm −2, highly relativistic plasmas can now be studied. The force exerted by light pulses with this extreme intensity has been used to accelerate beams of electrons and protons to energies of a million volts in distances of only microns. This acceleration gradient is a thousand times greater than in radio-frequency-based accelerators. Such novel compact laser-based radiation sources have been demonstrated to have parameters that are useful for research in medicine, physics and engineering. They might also someday be used to ignite controlled thermonuclear fusion. Ultrashort pulse duration particles and x-rays that are produced can resolve chemical, biological or physical reactions on ultrafast (femtosecond) timescales and on atomic spatial scales. These energetic beams have produced an array of nuclear reactions, resulting in neutrons, positrons and radioactive isotopes. As laser intensities increase further and laser-accelerated protons become relativistic, exotic plasmas, such as dense electron–positron plasmas, which are of astrophysical interest, can be created in the laboratory. This paper reviews many of the recent advances in relativistic laser–plasma interactions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48918/2/d308r2.pd

Method for Generating a Plasma Wave to Accelerate Electrons

The invention provides a method and apparatus for generating large amplitude nonlinear plasma waves, driven by an optimized train of independently adjustable, intense laser pulses. In the method, optimal pulse widths, interpulse spacing, and intensity profiles of each pulse are determined for each pulse in a series of pulses. A resonant region of the plasma wave phase space is found where the plasma wave is driven most efficiently by the laser pulses. The accelerator system of the invention comprises several parts: the laser system, also called beam source, which preferably comprises photo cathode electron source and RF-LINAC accelerator; electron photo-cathode triggering system; the electron diagnostics; and the feedback system between the electron diagnostics and the laser system. The system also includes plasma source including vacuum chamber, magnetic lens, and magnetic field means. The laser system produces a train of pulses that has been optimized to maximize the axial electric field amplitude of the plasma wave, and thus the electron acceleration, using the method of the invention