PAC09 - List of Authors (Clayton, C.E.)

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Clayton, C.E.

Paper	Title	Page
WE6RFP079	Length Scaling of the Electron Energy Gain in the Self-Guided Laser Wakefield Regime Using a 150 TW Ultra-Short Pulse Laser Beam	2982
	D.H. Froula, J. Bonlie, L. Divol, S.H. Glenzer, P. Michel, J. Palastro, D. Price, J.E. Ralph, J.S. Ross, C. Siders LLNL, Livermore, California C.E. Clayton, C. Joshi, K.A. Marsh, A.E. Pak UCLA, Los Angeles, California B.B. Pollock, G.R. Tynan UCSD, La Jolla, California
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and DE-FG03-92ER40727, and LDRD 06-ERD-056 Recent laser wakefield acceleration experiments at the Jupiter Laser Facility, Lawrence Livermore National Laboratory, will be discussed where the Callisto Laser has been upgraded and has demonstrated 60 fs, 10 J laser pulses. This 150 TW facility is providing the foundation to develop a GeV electron beam and associated betatron x-ray source for use on the petawatt high-repetition rate laser facility currently under development at LLNL. Initial self-guided experiments have produced high energy monoenergetic electrons while experiments using a multi-centimeter long magnetically controlled optical plasma waveguide are investigated. Measurements of the electron energy gain and electron trapping threshold using 150 TW laser pulses will be presented.
WE6RFP097	Simulations of 25 GeV PWFA Sections: Path Towards a PWFA Linear Collider	3025
	C. Huang, W. An, C.E. Clayton, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, M. Tzoufras UCLA, Los Angeles, California I. Blumenfeld, M.J. Hogan, N.A. Kirby, T.O. Raubenheimer, A. Seryi SLAC, Menlo Park, California T.C. Katsouleas Duke University, Durham, North Carolina P. Muggli USC, Los Angeles, California
	Funding: Work supported by DOE under contracts DE-FG03-92ER40727, DE-FG52-06NA26195, DE-FC02-07ER41500, DE-FG02-03ER54721. Recent Plasma Wake-Field Acceleration (PWFA) experiments at Stanford Linear Accelerator Center has demonstrated electron acceleration from 42GeV to 84GeV in less than one meter long plasma section. The accelerating gradient is above 50GeV/m, which is three orders of magnitude higher than those in current state-of-art RF linac. Further experiments are also planned with the goal of achieving acceleration of a witness bunch with high efficiency and good quality. Such PWFA sections with 25 GeV energy gain will be the building blocks for a staged TeV electron-positron linear collider concept based on PWFA (PWFA-LC). We conduct Particle-In-Cell simulations of these PWFA sections at both the initial and final witness beam energies. Different design options, such as Gaussian and shaped bunch profiles, self-ionized and pre-ionized plasmas, optimal bunch separation and plasma density are explored. Theoretical analysis of the beam-loading* in the blow-out regime of PWFA and simulation results show that highly efficient PWFA stages are possible. The simulation needs, code developments and preliminary simulation results for future collider parameters will be discussed. *M. Tzoufras et al, Phys. Rev. Lett. {10}1, 145002 (2008).
WE6RFP101	Two-Screen Method for Determining Electron Beam Energy and Deflection from Laser Wakefield Acceleration	3035
	B.B. Pollock, J.S. Ross, G.R. Tynan UCSD, La Jolla, California C.E. Clayton, C. Joshi, K.A. Marsh, A.E. Pak, T.-L. Wang UCLA, Los Angeles, California L. Divol, D.H. Froula, S.H. Glenzer, V. Leurent, J. Palastro, J.E. Ralph LLNL, Livermore, California
	We present experimental results showing the formation of a laser produced optical waveguide, suitable for laser guiding, when applying a high external magnetic field around a gas cell. This technique is directly applicable to wakefield acceleration and has been established at the Jupiter Laser Facility; an external magnetic field prevents radial heat transport, resulting in an increased electron temperature gradient [D. H. Froula et.al., Plasma Phys. Control. Fusion, 51, 024009 (2009)]. Interferometry and spatially resolved Thomson-scattering diagnostics measure the radial electron density profile, and show that multiple-centimeter long waveguides with minimum electron densities of 10¹⁷ to 10¹⁸ cm^-3 can be produced. Temporally resolved Thomson-scattering is also performed to characterize the evolution of the density channel in time. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 and was partially funded by the Laboratory Directed Research and Development Program under project tracking code 06-ERD-056.
FR5RFP016	Scaling and Transformer Ratio in a Plasma Wakefield Accelerator	4565
	I. Blumenfeld, F.-J. Decker, M.J. Hogan, R. Ischebeck, R.H. Iverson, N.A. Kirby, R. Siemann, D.R. Walz SLAC, Menlo Park, California C.E. Clayton, C. Huang, C. Joshi, W. Lu, K.A. Marsh, W.B. Mori, M. Zhou UCLA, Los Angeles, California T.C. Katsouleas, P. Muggli, E. Oz USC, Los Angeles, California
	High gradient acceleration of electrons has recently been achieved in meter scale plasmas at SLAC. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch lengths were varied systematically at constant charge. Here we investigate the correlation of peak beam current to the wake amplitude. The effect of beam head erosion will be discussed and an experimental limit on the transformer ratio set. The results are compared to simulation.