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in creator/contributor: "Leemans, W.P."

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Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic

The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

Date: June 1, 2010

Creator: Bakeman, M. S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC

to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By u… more

Date: May 4, 2009

Creator: Bakeman, M.S.; Fawley, W.M.; Leemans, W. P.; Nakamura, K.; Robinson, K.E.; Schroeder, C.B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Efficient Modeling of Laser-Plasma Accelerators with INF&RNO

The numerical modeling code INF&RNO (INtegrated Fluid& paRticle simulatioN cOde, pronounced"inferno") is presented. INF&RNO is an efficient 2D cylindrical code to model the interaction of a short laser pulse with an underdense plasma. The code is based on an envelope model for the laser while either a PIC or a fluid description can be used for the plasma. The effect of the laser pulse on the plasma is modeled with the time-averaged poderomotive force. These and other featu… more

Date: June 1, 2010

Creator: Benedetti, C.; Schroeder, C. B.; Esarey, E.; Geddes, C. G. R. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simulation of ionization effects for high-density positron drivers in future plasma wakefield experiments

The plasma wakefield accelerator (PWFA) concept has been proposed as a potential energy doubler for present or future electron-positron colliders. Recent particle-in-cell (PIC) simulations have shown that the self-fields of the required electron beam driver can tunnel ionize neutral Li, leading to plasma wake dynamics differing significantly from that of a preionized plasma. It has also been shown, for the case of a preionized plasma, that the plasma wake of a positron driver differs strongly f… more

Date: May 12, 2003

Creator: Bruhwiler, D. L.; Dimitrov, D. A.; Cary, J. R.; Esarey, E. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Particle-in-cell simulations of plasma accelerators and electron-neutral collisions

We present 2-D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approx}10{sup 16} W/cm{sup 2}) and high ({approx}10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simu… more

Date: October 1, 2001

Creator: Bruhwiler, David L.; Giacone, Rodolfo E.; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurements of Radiation Near An Atomic Spectral Line From the Interaction of a 30-GeV Electron Beam And a Long Plasma

Emissions produced or initiated by a 30 GeV electron beam propagating through a {approx}1 m long heat pipe oven containing neutral and partially ionized vapor have been measured near atomic spectral lines in a beam-plasma wakefield experiment. The Cerenkov spatial profile has been studied as a function of oven temperature and pressure, observation wavelength, and ionizing laser intensity and delay. The Cerenkov peak angle is affected by the creation of plasma; estimates of plasma and neutral de… more

Date: September 12, 2005

Creator: Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W. P.; Assmann, R.; Decker, F. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of … more

Date: January 1, 2001

Creator: Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W. P.; Assmann, R.; Decker, F.-J. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Femtosecond x-rays from Thomson scattering using laser wakefield accelerators

The possibility of producing femtosecond x-rays through Thomson scattering high power laser beams off laser wakefield generated relativistic electron beams is discussed. The electron beams are produced with either a self-modulated laser wakefield accelerator (SM-LWFA) or through a standard laser wakefield accelerator (LWFA) with optical injection. For a SM-LWFA (LWFA) produced electron beam, a broad (narrow) energy distribution is assumed, resulting in X-ray spectra that are broadband (monochro… more

Date: March 1, 2001

Creator: Catravas, P.; Esarey, E. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation sources and diagnostics with ultrashort electron bunches

The basic principles and design of radiation sources (transition radiation, Cerenkov radiation, radiation from periodic structures, etc.) and radiation-based diagnostics will be discussed, with emphasis on radiation from ultra-short electron bunches. Ultra-short electron bunches have the potential to produce high peak flux radiation sources that cover wavelength regimes where sources are currently not widely available (coherent THz/IR) as well as ultrashort X-ray pulses (3-100 fs). While radiat… more

Date: November 2, 2001

Creator: Catravas, P.; Esarey, E. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Wavefront Measurement for Laser-Guiding Diagnostic

The wavefront of a short laser pulse after interaction in a laser-plasma accelerator (LPA) was measured to diagnose laser-guiding quality. Experiments were performed on a 100 TW class laser at the LOASIS facility of LBNL using a hydrogenfilled capillary discharge waveguide. Laser-guiding with a pre-formed plasma channel allows the laser pulse to propagate over many Rayleigh lengths at high intensity and is crucial to accelerate electrons to the highest possible energy. Efficient coupling of las… more

Date: June 1, 2010

Creator: Chicago, University of; Laboratory, Lawrence Berkeley National; Shiraishi, S.; Gonsalves, A. J.; Lin, C.; Nakamura, K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Transverse envelope dynamics of a 28.5 GeV electron beam in a long plasma

The transverse dynamics of a 28.5 GeV electron beam propagating in a 1.4 m long, 0-2 x 10{sup 14} cm{sup -3} plasma are studied experimentally in the underdense or blow-out regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the s… more

Date: April 1, 2002

Creator: Clayton, C. E.; Blue, B. E.; Dodd, E. S.; Joshi, C.; Marsh, K. A.; Mori, W. B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design of 10 GeV laser wakefield accelerator stages with shaped laser modes

We present particle-in-cell simulations, using the VORPAL framework, of 10 GeV laser plasma wakefield accelerator stages. Scaling of the physical parameters with the plasma density allows us to perform these simulations at reasonable cost and to design high performance stages. In particular we show that, by choosing to operate in the quasi-linear regime, we can use higher order laser modes to tailor the focusing forces. This makes it possible to increase the matched electron beam radius and hen… more

Date: September 25, 2009

Creator: Cormier-Michel, Estelle; Esarey, E.; Geddes, C. G. R.; Geddes, C. G. R.; Leemans, W. P.; Bruhwiler, D. L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scaled simulations of a 10 GeV accelerator

Laser plasma accelerators are able to produce high quality electron beams from 1 MeV to 1 GeV. The next generation of plasma accelerator experiments will likely use a multi-stage approach where a high quality electron bunch is first produced and then injected into an accelerating structure. In this paper we present scaled particle-in-cell simulations of a 10 GeV stage in the quasi-linear regime. We show that physical parameters can be scaled to be able to perform these simulations at reasonable… more

Date: September 8, 2008

Creator: Cormier-Michel, Estelle; Geddes, C. G. R.; Esarey, E.; Schroeder, C. B.; Bruhwiler, D. L.; Paul, K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Femtosecond electron and x-ray generation by laser andplasma-based sources

The generation of ultra-short x-rays by Thomson scattering intense laser pulses from electron beams is discussed, including recent experimental results and methods for enhancing the x-ray flux. A high flux of x-rays in a femtosecond pulse requires the generation of femtosecond electron bunches and a head-on Thomson scattering geometry. The generation of ultrashort electron bunches in a plasma-based accelerator with an injection technique that uses two colliding laser pulses is discussed. Simula… more

Date: February 1, 2000

Creator: Esarey, E. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Betatron radiation from electron beams in plasma focusing channels

Spontaneous radiation emitted from an electron undergoing betatron motion is a plasma focusing channel is analyzed and applications to plasma wakefield accelerator experiments and to the ion channel laser (ICL) are discussed. Important similarities and differences between a free electron laser (FEL) and in an ICL are delineated. It is shown that the frequency of spontaneous radiation is a strong function of the betatron strength parameter a{sub {beta}}, which plays a similar role to that of the… more

Date: June 1, 2000

Creator: Esarey, E.; Catravas, P. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High Quality Electron Bunches up to 1 GeV from Laser Wakefield Acceleration at LBNL

Experiments at the LOASIS laboratory of LBNL havedemonstrated production of 100 MeV to 1 GeV electron bunches with lowenergy spread and low divergence from laser wakefield acceleration. Theradiation pressure of a 10 TW laser pulse, guided over 10 diffractionranges by a few-mm long plasma density channel, was used to drive anintense plasma wave (wakefield), producing electron bunches with energieson the order of 100 MeV and acceleration gradients on the order of 100GV/m. Beam energy was increase… more

Date: July 1, 2006

Creator: Esarey, E.; Nagler, B.; Gonsalves, A.J.; Toth, Cs.; Nakamura, K.; Geddes, C.G.R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Thermal effects in plasma-based accelerators

Finite plasma temperature can modify the structure of thewake field, reduce the wave-breaking field, and lead to self-trappedelectrons, which can degrade the electron bunch quality in a plasma-basedaccelerator. A relativistic warm fluid theory is used to describe theplasma temperature evolution and alterations to the structure of anonlinear periodic wave exited in a warm plasma. The trapping thresholdfor a plasma electron and the fraction of electrons trapped from athermal distribution are exam… more

Date: January 9, 2007

Creator: Esarey, E.; Schroeder, C. B.; Michel, E.; Shadwick, B. A.; Geddes, C. G. R. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Synchrotron radiation from electron beams in plasma focusing channels

Spontaneous radiation emitted from relativistic electrons undergoing betatron motion in a plasma focusing channel is analyzed and application to plasma wakefield accelerator experiments and to the ion channel laser (ICL) are discussed. Important similarities and differences between a free electron laser (FEL) and an ICL are delineated. It is shown that the frequency of spontaneous radiation is a strong function of the betatron strength parameter alpha-beta, which plays a similar role to that of… more

Date: December 6, 2001

Creator: Esarey, E.; Shadwick, B. A.; Catravas, P. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Beat wave injection of electrons into plasma waves using two interfering laser pulses

An electron injector concept that uses a single injection laser pulse colliding with a pump laser pulse in a plasma is analyzed. The pump pulse generates a large amplitude laser wakefield (plasma wave). The counter propagating injection pulse collides with the pump laser pulse to generate a beat wave with a slow phase velocity. The ponderomotive force of the slow beat wave is responsible for injecting plasma electrons into the wakefield near the back of the pump pulse. Test particle simulations… more

Date: March 4, 2004

Creator: Fubiani, G.; Esarey, E.; Schroeder, C. B. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Improvement of electron beam quality in optical injection schemesusing negative plasma density gradients

Enhanced electron trapping using plasma density down ramps as a method for improving the performance of laser injection schemes is proposed and analyzed. A decrease in density implies an increase in plasma wavelength, which can shift a relativistic electron from the defocusing to the focusing region of the accelerating wakefield, and a decrease in wake phase velocity, which lowers the trapping threshold. The specific method of two-pulse colliding pulse injector was examined using a three-dimens… more

Date: July 26, 2005

Creator: Fubiani, G.; Esarey, E.; Schroeder, C. B. & Leemans, W. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Scaled Simulation Design of High Quality Laser Wakefield Accelerator Stages

Design of efficient, high gradient laser driven wakefield accelerator (LWFA) stages using explicit particle-incell simulations with physical parameters scaled by plasma density is presented. LWFAs produce few percent energy spread electron bunches at 0.1-1 GeV with high accelerating gradients. Design tools are now required to predict and improve performance and efficiency of future LWFA stages. Scaling physical parameters extends the reach of explicit simulations to address applications includi… more

Date: May 4, 2009

Creator: Geddes, C. G. R.; Cormier-Michel, E.; Esarey, E.; Schroeder, C. B.; Leemans, W. P.; Bruhwiler, D. L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes

Laser-plasma collider designs point to staging of multiple accelerator stages at the 10 GeV level, which are to be developed on the upcoming BELLA laser, while Thomson Gamma source designs use GeV stages, both requiring efficiency and low emittance. Design and scaling of stages operating in the quasi-linear regime to address these needs are presented using simulations in the VORPAL framework. In addition to allowing symmetric acceleration of electrons and positrons, which is important for colli… more

Date: June 1, 2010

Creator: Geddes, C. G. R.; Cormier-Michel, E.; Esarey, E.; Schroeder, C. B.; Mullowney, P.; Paul, K. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mono-Energetic Beams from Laser Plasma Interactions

A laser driven wakefield accelerator has been tuned to produce high energy electron bunches with low emittance and energy spread by extending the interaction length using a plasma channel. Wakefield accelerators support gradients thousands of times those achievable in RF accelerators, but short acceleration distance, limited by diffraction, has resulted in low energy beams with 100 percent electron energy spread. In the present experiments on the L'OASIS laser, the relativistically intense driv… more

Date: May 9, 2005

Creator: Geddes, C. G. R.; Esarey, E.; Leemans, W. P.; Schroeder, C. B.; Toth, Cs.; van Tilborg, J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Low energy spread 100 MeV-1 GeV electron bunches from laserwakefiel d acceleration at LOASIS

Experiments at the LOASIS laboratory of LBNL recentlydemonstrated production of 100 MeV electron beams with low energy spreadand low divergence from laser wakefield acceleration. The radiationpressure of a 10 TW laser pulse guided over 10 diffraction ranges by aplasma density channel was used to drive an intense plasma wave(wakefield), producing acceleration gradients on the order of 100 GV/m ina mm-scale channel. Beam energy has now been increased from 100 to 1000MeV by using a cm-scale guidin… more

Date: August 1, 2006

Creator: Geddes, C. G. R.; Esarey, E.; Michel, P.; Nagler, B.; Nakamura, K.; Plateau, G. R. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department