Publications by Simon Hooker


Electron acceleration in a gas-discharge capillary

34th EPS Conference on Plasma Physics 2007, EPS 2007 - Europhysics Conference Abstracts 31 (2007) 57-60

A Popp, J Osterhoff, TP Rowlands-Rees, Z Major, M Fuchs, B Marx, R Hörlein, K Schmid, B Hidding, L Veisz, F Grüner, U Schramm, F Krausz, SM Hooker, S Karsch


GeV plasma accelerators driven in waveguides

PLASMA PHYS CONTR F 49 (2007) B403-B410

SM Hooker, E Brunetti, E Esarey, JG Gallacher, CGR Geddes, AJ Gonsalves, DA Jaroszynski, C Kamperidis, S Kneip, K Krushelnick, WP Leemans, SPD Mangles, CD Murphy, B Nagler, Z Najmudin, K Nakamura, PA Norreys, D Panasenko, TP Rowlands-Rees, CB Schroeder, CS Toth, R Trines

During the last few years laser-driven plasma accelerators have been shown to generate quasi-monoenergetic electron beams with energies up to several hundred MeV. Extending the output energy of laser-driven plasma accelerators to the GeV range requires operation at plasma densities an order of magnitude lower, i.e. 10(18) cm(-3), and increasing the distance over which acceleration is maintained from a few millimetres to a few tens of millimetres. One approach for achieving this is to guide the driving laser pulse in the plasma channel formed in a gas-filled capillary discharge waveguide. We present transverse interferometric measurements of the evolution of the plasma channel formed and compare these measurements with models of the capillary discharge. We describe in detail experiments performed at Lawrence Berkeley National Laboratory and at Rutherford Appleton Laboratory in which plasma accelerators were driven within this type of waveguide to generate quasi-monoenergetic electron beams with energies up to I GeV.


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


Performance of capillary discharge guided laser plasma wakefield accelerator

2007 IEEE PARTICLE ACCELERATOR CONFERENCE, VOLS 1-11 (2007) 2222-+

K Nakamura, E Esarey, CGR Geddes, AJ Gonsalves, WP Leernans, D Panasenko, CB Schroeder, C Toth, SM Hooker, IEEE


Comparison of parallel and perpendicular polarized counterpropagating light for suppressing high harmonic generation

Journal of the Optical Society of America B: Optical Physics 24 (2007) 2421-2427

M Landreman, K O'Keeffe, T Robinson, M Zepf, B Dromey, SM Hooker

The use of counterpropagating laser pulses to suppress high harmonic generation (HHG) is investigated experimentally for pulses polarized parallel or perpendicular to the driving laser pulse. It is shown for the first time that perpendicularly polarized pulses can suppress HHG. The intensity of the counterpropagating pulse required for harmonic suppression is found to be much larger for perpendicular polarization than for parallel polarization, in good agreement with simple models of the harmonic suppression. These results have applications to quasi-phase-matching of HHG with trains of counterpropagating pulses. © 2007 Optical Society of America.


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.


Energy extraction from pulsed amplified stimulated emission lasers operating under conditions of strong saturation

JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS 23 (2006) 1057-1067

SM Hooker, DJ Spence


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 CO2laser 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


Inverse free electron lasers and laser wakefield acceleration driven by CO<inf>2</inf>lasers

Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364 (2006) 611-622

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

The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e-beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e-beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e-beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO2laser beam. © 2006 The Royal Society.


High quality electron bunches up to 1 GeV from laser wakefield acceleration at LBNL

AIP Conference Proceedings 877 (2006) 8-14

E Esarey, B Nagler, AJ Gonsalves, C Toth, K Nakamura, CGR Geddes, CB Schroeder, J Van Tilborg, S Hooker, WP Leemans, E Michel, J Cary, D Bruhwiler

Experiments at the LOASIS laboratory of LBNL have demonstrated production of 100 MeV to 1 GeV electron bunches 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 few-mm long plasma density channel, was used to drive an intense plasma wave (wakefield), producing electron bunches with energies on the order of 100 MeV and acceleration gradients on the order of 100 GV/m. Beam energy was increased from 100 MeV to 1 GeV by using a few-cm long 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. © 2006 American Institute of Physics.


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 Xe8+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 Xe8+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 CO2laser. 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 Ar7+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.

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