The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

C E Clayton - One of the best experts on this subject based on the ideXlab platform.

  • high field plasma acceleration in a high ionization potential gas
    Nature Communications, 2016
    Co-Authors: S Corde, E Adli, James Allen, C I Clarke, B Clausse, C E Clayton, J P Delahaye, J Frederico, S Gessner, S Z Green
    Abstract:

    Plasma accelerators driven by particle beams are a promising technology, but the acceleration distance and Energy Gain are strongly limited by head erosion in a high-ionization-potential gas. Here the authors observe up to 130% Energy boost in a self-focused electron beam, with limited head erosion.

  • 9 GeV Energy Gain in a beam-driven plasma wakefield accelerator
    Plasma Physics and Controlled Fusion, 2016
    Co-Authors: M Litos, S Corde, E Adli, C I Clarke, C E Clayton, J Frederico, S Z Green, J M Allen, S J Gessner, M J Hogan
    Abstract:

    An electron beam has Gained a maximum Energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square Energy spread was 5.0%. The mean accelerated charge and Energy Gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV/m at the spectral peak. The mean Energy spread of the data set was 5.1%. These results are consistent with the extrapolation of the previously reported Energy Gain results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.

  • Energy doubling of 42 gev electrons in a metre scale plasma wakefield accelerator
    Nature, 2007
    Co-Authors: I Blumenfeld, C E Clayton, M J Hogan, C Joshi, F J Decker, C Huang, R Ischebeck, R Iverson, T Katsouleas, N Kirby
    Abstract:

    The Energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant Energy Gain. Here we show that an Energy Gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose Energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of approximately 52 GV m(-1). This effectively doubles their Energy, producing the Energy Gain of the 3-km-long SLAC accelerator in less than a metre for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-Energy physics applications.

  • multi gev Energy Gain in a plasma wakefield accelerator
    Physical Review Letters, 2005
    Co-Authors: M J Hogan, C E Clayton, C D Barnes, F J Decker, S Deng, P Emma, C Huang, R H Iverson, D K Johnson, C Joshi
    Abstract:

    A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. A 28.5 GeV electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused to a transverse spot size of 10 microm at the entrance of a 10 cm long column of lithium vapor with density 2.8 x 10(17) atoms/cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons. These electrons return one-half plasma period later driving a large amplitude plasma wake that in turn accelerates particles in the back of the bunch by more than 2.7 GeV.

  • high Energy Gain of trapped electrons in a tapered diffraction dominated inverse free electron laser
    Physical Review Letters, 2005
    Co-Authors: P Musumeci, C E Clayton, R J England, Ya S Tochitsky, S Boucher, A Doyuran, C Joshi, C Pellegrini, J E Ralph, J B Rosenzweig
    Abstract:

    Energy Gain of trapped electrons in excess of 20 MeV has been demonstrated in an inverse-free-electron-laser (IFEL) accelerator experiment. A 14.5 MeV electron beam is copropagated with a 400 GW CO2 laser beam in a 50 cm long undulator strongly tapered in period and field amplitude. The Rayleigh range of the laser, approximately 1.8 cm, is much shorter than the undulator length yielding a diffraction-dominated interaction. Experimental results on the dependence of the acceleration on injection Energy, laser focus position, and laser power are discussed. Simulations, in good agreement with the experimental data, show that most of the Energy Gain occurs in the first half of the undulator at a gradient of 70 MeV/m and that the structure in the measured Energy spectrum arises because of higher harmonic IFEL interaction in the second half of the undulator.

GERHARD KORN - One of the best experts on this subject based on the ideXlab platform.

  • Unlimited Energy Gain in the laser-driven radiation pressure dominant acceleration of ions
    Physics of Plasmas, 2010
    Co-Authors: E. Yu. Echkina, I. N. Inovenkov, T. Zh. Esirkepov, Francesco Pegoraro, Masaki Kando, GERHARD KORN
    Abstract:

    The Energy of the ions accelerated by an intense electromagnetic wave in the radiation pressure dominated regime can be greatly enhanced by a transverse expansion of a thin target. The expansion decreases the number of accelerated ions in the irradiated region increasing the Energy and the longitudinal velocity of the remaining ions. In the relativistic limit, the ions become phase locked with respect to the electromagnetic wave resulting in an unlimited ion Energy Gain. This effect and the use of optimal laser pulse shape provide a new approach for greatly enhancing the Energy of laser accelerated ions.

  • unlimited Energy Gain in the laser driven radiation pressure dominant acceleration of ions
    arXiv: Plasma Physics, 2009
    Co-Authors: Sergei V Bulanov, I. N. Inovenkov, Francesco Pegoraro, Masaki Kando, Yu E Echkina, Zh T Esirkepov, GERHARD KORN
    Abstract:

    The Energy of the ions accelerated by an intense electromagnetic wave in the radiation pressure dominated regime can be greatly enhanced due to a transverse expansion of a thin target. The expansion decreases the number of accelerated ions in the irradiated region increasing the Energy and the longitudinal velocity of remaining ions. In the relativistic limit, the ions become phase-locked with respect to the electromagnetic wave resulting in the unlimited ion Energy Gain. This effect and the use of optimal laser pulse shape provide a new approach for great enhancing the Energy of laser accelerated ions.

C Joshi - One of the best experts on this subject based on the ideXlab platform.

  • estimation of direct laser acceleration in laser wakefield accelerators using particle in cell simulations
    arXiv: Plasma Physics, 2015
    Co-Authors: J L Shaw, N Lemos, K A Marsh, F S Tsung, W B Mori, C Joshi
    Abstract:

    Many current laser wakefield acceleration (LWFA) experiments are carried out in a regime where the laser pulse length is on the order of or longer than the wake wavelength and where ionization injection is employed to inject electrons into the wake. In these experiments, the trapped electrons will co-propagate with the longitudinal wakefield and the transverse laser field. In this scenario, the electrons can Gain a significant amount of Energy from both the direct laser acceleration (DLA) mechanism as well as the usual LWFA mechanism. Particle-in-cell (PIC) codes are frequently used to discern the relative contribution of these two mechanisms. However, if the longitudinal resolution used in the PIC simulations is inadequate, it can produce numerical heating that can overestimate the transverse motion, which is important in determining the Energy Gain due to DLA. We have therefore carried out a systematic study of this LWFA regime by varying the longitudinal resolution of PIC simulations from the standard, best-practice resolution of 30 points per laser wavelength to four times that value and then examining the Energy Gain characteristics of both the highest-Energy electrons and the bulk electrons. By calculating the contribution of DLA to the final energies of the electrons produced from the LWFA, we find that although the transverse momentum and oscillation radii are over-estimated in the lower-resolution simulations, this over-estimation does not lead to artificial Energy Gain by DLA. Rather, the DLA contribution to the highest-Energy electrons is larger in the higher-resolution cases because the DLA resonance is better maintained. Thus, even at the highest longitudinal resolutions, DLA contributes a significant portion of the Energy Gained by the highest-Energy electrons and also contributes to accelerating the bulk of the charge in the electron beam produced by the LWFA.

  • Energy doubling of 42 gev electrons in a metre scale plasma wakefield accelerator
    Nature, 2007
    Co-Authors: I Blumenfeld, C E Clayton, M J Hogan, C Joshi, F J Decker, C Huang, R Ischebeck, R Iverson, T Katsouleas, N Kirby
    Abstract:

    The Energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant Energy Gain. Here we show that an Energy Gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose Energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of approximately 52 GV m(-1). This effectively doubles their Energy, producing the Energy Gain of the 3-km-long SLAC accelerator in less than a metre for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-Energy physics applications.

  • multi gev Energy Gain in a plasma wakefield accelerator
    Physical Review Letters, 2005
    Co-Authors: M J Hogan, C E Clayton, C D Barnes, F J Decker, S Deng, P Emma, C Huang, R H Iverson, D K Johnson, C Joshi
    Abstract:

    A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. A 28.5 GeV electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused to a transverse spot size of 10 microm at the entrance of a 10 cm long column of lithium vapor with density 2.8 x 10(17) atoms/cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons. These electrons return one-half plasma period later driving a large amplitude plasma wake that in turn accelerates particles in the back of the bunch by more than 2.7 GeV.

  • high Energy Gain of trapped electrons in a tapered diffraction dominated inverse free electron laser
    Physical Review Letters, 2005
    Co-Authors: P Musumeci, C E Clayton, R J England, Ya S Tochitsky, S Boucher, A Doyuran, C Joshi, C Pellegrini, J E Ralph, J B Rosenzweig
    Abstract:

    Energy Gain of trapped electrons in excess of 20 MeV has been demonstrated in an inverse-free-electron-laser (IFEL) accelerator experiment. A 14.5 MeV electron beam is copropagated with a 400 GW CO2 laser beam in a 50 cm long undulator strongly tapered in period and field amplitude. The Rayleigh range of the laser, approximately 1.8 cm, is much shorter than the undulator length yielding a diffraction-dominated interaction. Experimental results on the dependence of the acceleration on injection Energy, laser focus position, and laser power are discussed. Simulations, in good agreement with the experimental data, show that most of the Energy Gain occurs in the first half of the undulator at a gradient of 70 MeV/m and that the structure in the measured Energy spectrum arises because of higher harmonic IFEL interaction in the second half of the undulator.

M J Hogan - One of the best experts on this subject based on the ideXlab platform.

  • 9 GeV Energy Gain in a beam-driven plasma wakefield accelerator
    Plasma Physics and Controlled Fusion, 2016
    Co-Authors: M Litos, S Corde, E Adli, C I Clarke, C E Clayton, J Frederico, S Z Green, J M Allen, S J Gessner, M J Hogan
    Abstract:

    An electron beam has Gained a maximum Energy of 9 GeV per particle in a 1.3 m-long electron beam-driven plasma wakefield accelerator. The amount of charge accelerated in the spectral peak was 28.3 pC, and the root-mean-square Energy spread was 5.0%. The mean accelerated charge and Energy Gain per particle of the 215 shot data set was 115 pC and 5.3 GeV, respectively, corresponding to an acceleration gradient of 4.0 GeV/m at the spectral peak. The mean Energy spread of the data set was 5.1%. These results are consistent with the extrapolation of the previously reported Energy Gain results using a shorter, 36 cm-long plasma source to within 10%, evincing a non-evolving wake structure that can propagate distances of over a meter in length. Wake-loading effects were evident in the data through strong dependencies observed between various spectral properties and the amount of accelerated charge.

  • Energy doubling of 42 gev electrons in a metre scale plasma wakefield accelerator
    Nature, 2007
    Co-Authors: I Blumenfeld, C E Clayton, M J Hogan, C Joshi, F J Decker, C Huang, R Ischebeck, R Iverson, T Katsouleas, N Kirby
    Abstract:

    The Energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant Energy Gain. Here we show that an Energy Gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose Energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of approximately 52 GV m(-1). This effectively doubles their Energy, producing the Energy Gain of the 3-km-long SLAC accelerator in less than a metre for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-Energy physics applications.

  • multi gev Energy Gain in a plasma wakefield accelerator
    Physical Review Letters, 2005
    Co-Authors: M J Hogan, C E Clayton, C D Barnes, F J Decker, S Deng, P Emma, C Huang, R H Iverson, D K Johnson, C Joshi
    Abstract:

    A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. A 28.5 GeV electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused to a transverse spot size of 10 microm at the entrance of a 10 cm long column of lithium vapor with density 2.8 x 10(17) atoms/cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons. These electrons return one-half plasma period later driving a large amplitude plasma wake that in turn accelerates particles in the back of the bunch by more than 2.7 GeV.

Cornel Sultan - One of the best experts on this subject based on the ideXlab platform.

  • proportional damping approximation using the Energy Gain and simultaneous perturbation stochastic approximation
    Mechanical Systems and Signal Processing, 2010
    Co-Authors: Cornel Sultan
    Abstract:

    The design of vector second-order linear systems for accurate proportional damping approximation is addressed. For this purpose an error system is defined using the difference between the generalized coordinates of the non-proportionally damped system and its proportionally damped approximation in modal space. The accuracy of the approximation is characterized using the Energy Gain of the error system and the design problem is formulated as selecting parameters of the non-proportionally damped system to ensure that this Gain is sufficiently small. An efficient algorithm that combines linear matrix inequalities and simultaneous perturbation stochastic approximation is developed to solve the problem and examples of its application to tensegrity structures design are presented.

  • published in mechanical systems and signal processing 24 2010 2210 2224 proportional damping approximation using the Energy Gain and simultaneous perturbation stochastic approximation
    2010
    Co-Authors: Cornel Sultan
    Abstract:

    The design of vector second order linear systems for accurate proportional damping approximation is addressed. For this purpose an error system is defined using the difference between the generalized coordinates of the non-proportionally damped system and its proportionally damped approximation in modal space. The accuracy of the approximation is characterized using the Energy Gain of the error system and the design problem is formulated as selecting parameters of the non-proportionally damped system to ensure that this Gain is sufficiently small. An efficient algorithm that combines Linear Matrix Inequalities and Simultaneous Perturbation Stochastic Approximation is developed to solve the problem and examples of its application to tensegrity structures design are presented.

  • design of structures for proportional damping approximation using the Energy Gain
    50th AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference, 2009
    Co-Authors: Cornel Sultan
    Abstract:

    NLIKE inertial and stiffness characteristics, which can be easily measured in static conditions, damping, a dynamic characteristic, is more difficult to quantify. Hence, in many cases the artificial Rayleigh damping model, which assumes that the damping matrix is a linear combination of the mass and stiffness matrices, is used. Rayleigh damping (or a generalization of it) is preferred because it leads to the ideal situation of a proportionally damped linear model of the structure’s dynamics, but it is neither a physics based nor a data based model. When the source of damping can be identified and accurately modeled using physics principles the Rayleigh damping assumption (or any artificial damping model for that matter) is not recommended. One example is that of tensegrity structures: the major damping sources can be easily identified, the joints and the tendons, and for these elements reliable physics based damping models can be built. However, in most cases the resulting linearized dynamics models are not proportionally damped. In general, the likelihood of obtaining non-proportionally damped models will increase due to our enhanced ability to accurately model damping using physics principles. Even if a system is not proportionally damped, one would still like to be able to approximate it with a proportionally damped system. For structures, usually described using models with many degrees of freedom, such models are very advantageous because they allow the replacement of non-proportionally damped models with decoupled models, which can be easily used for control design, fast computations, etc. This paper, which is strongly related to Ref. 6, pursues the idea of designing the structure such that it yields a linearized dynamics model that is “close” to a proportionally damped one. In Ref. 6 the design of structures for proportional damping approximation was investigated by exploiting only one, indirect factor that influences the accuracy of the approximation, namely the separation between natural frequencies. It was ascertained that separation