Publications by Simon Hooker


GeV electron beams from a laser-plasma accelerator

2006 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 (2006) 538-+

CB Schroeder, C Toth, B Nagler, AJ Gonsalves, K Nakamura, CGR Geddes, E Esarey, SM Hooker, WP Leemans, IEEE


Laser-driven particle accelerators: new sources of energetic particles and radiation - Introduction

PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES 364 (2006) 553-557

SM Hooker, DA Jaroszynski, K Burnett


Low energy spread 100 MeV-1 GeV electron bunches from laser wakefield acceleration at loasis

23rd International Linear Accelerator Conference, LINAC 2006 - Proceedings (2006) 806-808

CGR Geddes, E Esarey, P Michel, B Nagler, K Nakamura, GR Plateau, CB Schroeder, BA Shadwick, C Toth, J Van Tilborg, WP Leemans, SM Hooker, AJ Gonsalves, E Michel, JR Cary, D Bruhwiler

Experiments at the LOASIS laboratory of LBNL recently demonstrated production of 100 MeV electron beams with low energy spread and low divergence from laser wakefield acceleration. The radiation pressure of a 10 TW laser pulse guided over 10 diffraction ranges by a plasma density channel was used to drive an intense plasma wave (wakefield), producing acceleration gradients on the order of 100 GV/m in a mm-scale channel. Beam energy has now been increased from 100 to 1000 MeV by using a cm-scale guiding channel at lower density, driven by a 40 TW laser, demonstrating the anticipated scaling to higher beam energies. Particle simulations indicate that the low energy spread beams were produced from self trapped electrons through the interplay of trapping, loading, and dephasing. Other experiments and simulations are also underway to control injection of particles into the wake, and hence improve beam quality and stability further.


Update on seeded SM-LWFA and pseudo-resonant LWFA experiments - (STELLA-LW)

AIP Conference Proceedings 877 (2006) 534-540

WD Kimura, NE Andreev, M Babzien, DB Cline, X Ding, SM Hooker, E Kallos, TC Katsouleas, KP Kusche, SV Kuznetsov, P Muggli, IV Pavlishin, IV Pogorelsky, AA Pogosova, LC Steinhauer, D Stolyarov, A Ting, V Yakimenko, A Zigler, F Zhou

The Staged Electron Laser Acceleration - Laser Wakefield (STELLA-LW) experiment is investigating two new methods for laser wakefield acceleration (LWFA) using the TW CO 2 laser available at the Brookhaven National Laboratory Accelerator Test Facility. The first is seeded self-modulated LWFA where an ultrashort electron bunch (seed) precedes the laser pulse to generate a wakefield that the laser pulse subsequently amplifies. The second is pseudo-resonant LWFA where nonlinear pulse steepening of the laser pulse occurs in the plasma allowing the laser pulse to generate significant wakefields. The status of these experiments is reviewed. Evidence of wakefield generation caused by the seed bunches has been obtained as well as preliminary energy gain measurements of a witness bunch following the seeds. Comparison with a 1-D linear model for the wakefield generation appears to agree with the data. © 2006 American Institute of Physics.


GeV laser-plasma electron acceleration in a cm-scale capillary waveguide

Optics InfoBase Conference Papers (2006)

K Nakamura, C Tóth, B Nagler, CGR Geddes, CB Schroeder, E Esarey, WP Leemans, AJ Gonsalves, SM Hooker

33 mm plasma channels produced in a gas-filled capillary discharge and 40 TW, 40 fs laser pulses were used to produce GeV electron beams in a multi-table-top setup. © 2006 Optical Society of America.


GeV laser-plasma electron acceleration in a cm-scale capillary waveguide

Optics InfoBase Conference Papers (2006)

K Nakamura, C Tóth, B Nagler, CGR Geddes, CB Schroeder, E Esarey, WP Leemans, AJ Gonsalves, SM Hooker

33 mm plasma channels produced in a gas-filled capillary discharge and 40 TW, 40 fs laser pulses were used to produce GeV electron beams in a multi-table-top setup. ©2006 Optical Society of America.


GeV laser-plasma electron acceleration in a cm-scale capillary waveguide

Optics InfoBase Conference Papers (2006)

K Nakamura, C Tóth, B Nagler, CGR Geddes, CB Schroeder, E Esarey, WP Leemans, AJ Gonsalves, SM Hooker

33 mm plasma channels produced in a gas-filled capillary discharge and 40 TW, 40 fs laser pulses were used to produce GeV electron beams in a multi-table-top setup. © 2006 Optical Society of America.


GeV laser-plasma electron acceleration in a cm-scale capillary waveguide

Optics InfoBase Conference Papers (2006)

K Nakamura, C Tóth, B Nagler, CGR Geddes, CB Schroeder, E Esarey, WP Leemans, AJ Gonsalves, SM Hooker

33 mm plasma channels produced in a gas-filled capillary discharge and 40 TW, 40 fs laser pulses were used to produce GeV electron beams in a multi-table-top setup. © 2006 Optical Society of America.


GeV electron beams from a centimetre-scale accelerator

Nature Physics 2 (2006) 696-699

SM Hooker, W. P. Leemans, B. Nagler, Anthony J. Gonsalves


Collisional lasers at 41.8 nm in a guided regime

J PHYS IV 127 (2005) 33-37

I Bettaibi, S Sebban, T Mocek, CM McKenna, B Cros, A Butler, DJ Spence, G Maynard, AJ Gonsavles, SM Hooker


Progress in optic-field-ionization soft X-ray lasers at LOA

LASER PART BEAMS 23 (2005) 351-356

T Mocek, S Sebban, I Bettaibi, P Zeitoun, G Faivre, B Cros, G Maynard, A Butler, CM McKenna, DJ Spence, A Gonsavles, SM Hooker, V Vorontsov, S Hallou, M Fajardo, S Kazamias, S Le Pape, P Mercere, AS Morlens, C Valentin, P Balcou

We give on overview of recent advances in collisionally pumped optical field-ionization soft X-ray lasers developed at LOA. Saturated amplification has been achieved on the 5d-5p transition in Xe8+ at 41.8 nm, and on the 4d-4p transition in Kr8+ at 32.8 nm. We demonstrate a significant increase of the energy output from the Xe8+ laser driven within two types of wave-guide. Finally, we present results of a pioneering work aimed to set up and characterize the first true soft X-ray laser chain.


Dramatic enhancement of xuv laser output using a multimode gas-filled capillary waveguide

Physical Review A - Atomic, Molecular, and Optical Physics 71 (2005)

T Mocek, CM McKenna, B Cros, S Sebban, DJ Spence, G Maynard, I Bettaibi, V Vorontsov, AJ Gonsavles, SM Hooker

We report a significant increase of the output of a 41.8-nm Xe 8+ laser achieved by means of multimode guiding of high-intensity femtosecond laser pulses in a gas-filled dielectric capillary tube. The optimized lasing signal from a 15-mm-long capillary was nearly an order of magnitude higher than that from a gas cell of the same length. Simulations of the propagation of the pump laser pulse in the capillary confirmed that this enhancement is due to reflections from the capillary wall, which increase the length of the Xe 8+ plasma column generated. The influence of gas pressure and focusing position on the lasing is also presented. © 2005 The American Physical Society.


Pseudoresonant laser wakefield acceleration driven by 10.6-μm laser light

IEEE Transactions on Plasma Science 33 (2005) 3-7

WD Kimura, NE Andreev, M Babzien, I Ben-Zvi, DB Cline, CE Dilley, SC Gottschalk, SM Hooker, KP Kusche, SV Kuznetsov, IV Pavlishin, IV Pogorelsky, AA Pogosova, LC Steinhauer, A Ting, V Yakimenko, A Zigler, F Zhou

This paper describes an experiment to demonstrate, for the first time, laser wakefield acceleration (LWFA), driven by 10.6-μm light from a CO 2 laser. This experiment is also noteworthy because it will operate in a pseudoresonant LWFA regime, in which the laser-pulse-length is too long for resonant LWFA, but too short for self-modulated LWFA. Nonetheless, high acceleration gradients are still possible. This experiment builds upon an earlier experiment called staged electron laser acceleration (STELLA), where efficient trapping and monoenergetic laser acceleration of electrons were demonstrated using inverse free electron lasers. The aim is to apply the STELLA approach of laser-driven microbunch formation followed by laser-driven trapping and acceleration to LWFA. These capabilities are important for a practical electron linear accelerator based upon LWFA. © 2005 IEEE.


Simulations of recombination lasing in Ar<sup>7+</sup> driven by optical field ionization in a capillary discharge waveguide

Optics Communications 249 (2005) 501-513

DJ Spence, SM Hooker

We present calculations of the small-signal gain coefficient, gain length, and output energy of a recombination laser in Ar 7+ driven by optical field ionization. Simulations are presented for both 400 and 800 nm pump radiation, and for two targets containing mixtures of argon and hydrogen: a gas cell, and a gas-filled capillary discharge waveguide. Extremely high values for the small-signal gain coefficient are calculated for the 4s-3p transition at 23.2 nm using a pump wavelength of 400 nm for both the gas cell and waveguide. Operation in the waveguide is predicted to greatly increase the XUV laser output owing to a large increase of the gain length. The calculations also show that use of the waveguide allows significant single-pass gain to be achieved even with pump radiation of 800 nm wavelength. © 2005 Elsevier B.V. All rights reserved.


Effects of polarization on inverse Bremsstrahlung heating of a plasma.

Phys Rev E Stat Nonlin Soft Matter Phys 72 (2005) 036402-

N David, SM Hooker

A molecular dynamic (MD) code is used to compare the rates of heating by inverse Bremsstrahlung (IB) for circularly and linearly polarized radiation. For low intensities the heating rate is found to be independent of polarization. However, at higher intensities the variation of the heating rate with the radiation intensity is found to exhibit a sharper peak for circularly polarized than linearly polarized radiation. This difference is explained in terms of differences in the variation of the electron quiver speed during the optical cycle for linearly and circularly polarized radiation. An analytical expression--which includes a term which is nonlinear in the density of the plasma--for the rate of IB heating is fitted to the rates calculated by the MD code.


Application of the gas-filled capillary discharge waveguide to laser-plasma acceleration

AIP CONF PROC 737 (2004) 825-831

DJ Spence, AJ Gonsalves, CM McKenna, SM Hooker

The application of the gas-filled capillary discharge waveguide to laser-plasma accelerators is reviewed. The results of experiments to guide high-intensity laser pulses in capillaries with circular or square cross-sections are described. The relation between capillary diameter, guided spot size, and plasma density are explored, and a possible new hybrid regime of guiding is identified.


A review of laser guiding experiments

AIP CONF PROC 737 (2004) 125-136

SM Hooker

In many cases the length over which particles can be accelerated in a laser-driven plasma accelerator is limited by refraction or diffraction of the driving laser pulse. In order to overcome this limitation the driving pulse must be guided or channeled through the plasma, In this paper we briefly review of the techniques used to guide laser pulses with peak intensities up to 10(19) W cm(-2), and describe recent experimental results.


41.8-nm Xe<sup>8+</sup>laser driven in a plasma waveguide

Physical Review A - Atomic, Molecular, and Optical Physics 70 (2004)

A Butler, AJ Gonsalves, CM McKenna, DJ Spence, SM Hooker, S Sebban, T Mocek, I Betttaibi, B Cros

The results of the first experimental demonstration of a short-wavelength laser driven within a gas-filled capillary-discharge waveguide were described. The xenon gas was mixed with the hydrogen and strong lasing on the 4d 9 5d-4d 9 5p transition in Xe 8+ at 41.8 nm was observed. Analysis shows that lasing was strongly correlated with good guiding of the pump pulse and numerical simulations indicate that gain is likely to have been achieved over a significant fraction of the 30 mm length of the capillary. The success of this proof-of-principle experiment suggests that this and other short-wavelength lasers could be driven within waveguides of this type, leading to increased energy output and reduced beam divergence.


Progress on collisionally pumped optical-field-ionization soft X-ray lasers

IEEE Journal on Selected Topics in Quantum Electronics 10 (2004) 1351-1362

S Sebban, T Mocek, I Bettaibi, B Cros, G Maynard, A Butler, AJ Gonzalves, GM McKenna, DJ Spence, SM Hooker, LM Upcraft, P Breger, P Agostini, S Le Pape, P Zeitoun, C Valentin, P Balcou, D Ros, S Kazamias, A Klisnick, G Jamelot, B Rus, JF Wyart

We present the status of optical field ionization soft X-ray lasers. The amplifying medium is generated by focusing a high-energy circularly polarized 30-fs 10-Hz Ti: sapphire laser system in a gaseous medium. Using xenon or krypton, strong laser emission at 41.8 and 32.8 nm, respectively, has been observed. After presenting the basis of the physics, we present recent characterization of the sources as well as dramatic improvement of their performances using the waveguiding technique.


Molecular-dynamic calculation of the inverse-bremsstrahlung heating of non-weakly-coupled plasmas

Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 70 (2004)

N David, DJ Spence, SM Hooker

The inverse bremsstrahlung (IB) heating rates of a plasma as a function of density and laser intensity were calculated using a molecular dynamic (MD) code. The code belonged to the class of particle-particle-particle-mesh codes. The equations solved by the MD code avoided several assumptions which were inherent to alternative methods. The results of the MD code were compared to previous results for plasmas of low coupling. The results of the calculations for dense, moderately coupled plasmas were also presented. An analytic expression for the IB heating rate, based on a fit to the rates calculated by MD code, was also presented.

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