PAC2013 - List of Authors (Vieira, J.)

Paper	Title	Page
MOPAC02	Electron and Positron Bunch Self-modulation Experiments at SLAC-FACET	84
	P. Muggli MPI, Muenchen, Germany E. Adli, S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos SLAC, Menlo Park, California, USA Y. Fang USC, Los Angeles, California, USA C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA N.C. Lopes, L.O. Silva, J. Vieira Instituto Superior Tecnico, Lisbon, Portugal O. Reimann MPI-P, München, Germany
	A self-modulated proton-driven plasma wakefield acceleration experiment is being designed at CERN and will occur within 3-5 years. Uncompressed 20GeV lepton bunches currently available at SLAC-FACET could be used to test key physics of the CERN experiment (e.g. self-modulation instability (SMI), SMI seeding, ion motion, hosing, differences between electrons (e-) and positrons (e+), etc). The E-209 collaboration was formed to carry SMI experiments at SLAC-FACET. Here we show through full-scale Osiris simulations that electron self-modulation grows and saturates in less than 10cm. Wakefield excitation in the blowout regime leads to acceleration gradients in excess of 20GeV/m. The self-modulated e^- bunch then sustains stable wakefields over meter-long plasmas. As a result, 7(12)GeV e^- energy gain(loss) could be observed. In the blowout regime, most of the wakefield phase defocuses e+. Thus, uncompressed e⁺ bunches drive lower acceleration gradients, but still in excess of 10GeV/m, over 1m of plasma. We will discuss the experimental setup, diagnostics to measure SMI (e.g. CTR, energy spectrometer, OTR, etc) and expected results. First experimental results may also be available. J. Vieira et al., Phys. Plasmas 19, 063105 (2012).

MOPAC47	Simulation of Laser Wakefield Acceleration in the Lorentz Boosted Frame with UPIC-EMMA	168
	P. Yu, W. An, V.K. Decyk, W.B. Mori, F.S. Tsung UCLA, Los Angeles, California, USA R.A. Fonseca, L.O. Silva, J. Vieira Instituto Superior Tecnico, Lisbon, Portugal W. Lu, X.L. Xu TUB, Beijing, People's Republic of China
	Funding: Work supported by the US DoE under grants DE-SC0008491, DE-FG02-92- ER40727, DE-SC0008316 and DE-SC0007970, and by National Science Foundation under grants PHY-0936266, PHY-0960344 and PHY-0934856. Simulation of laser wakefield accelerator (LWFA) in the Lorentz boosted frame, in which the laser and plasma spatial scales are comparable, can lead to computational time speed-ups to several orders of magnitude. In these simulation the relativistic drifting plasma inevitably induces a high frequency numerical instability. To reduce this numerical instability, we developed an EM-PIC code, UPIC-EMMA, based on the components of UCLA PIC framework (UPIC) which uses a spectral solver to advance the electromagnetic field in the Fourier space. With a low pass or "ring" filter implemented in the spectral solver, the numerical instability can be eliminated. In this paper we describe the new code, UPIC-EMMA, and present results from the code of LWFA simulation in the Lorentz boosted frame. These include the modeling cases where there are no self-trapped electrons, and modeling the self-trapped regime. Detailed comparison among Lorentz boosted frame results and lab frame results obtained from OSIRIS are given. We have used UPIC-EMMA to study LWFA in the self-guided regime to 100 GeV and good agreement was found with analytical scaling.

Paper

Title

Page

Electron and Positron Bunch Self-modulation Experiments at SLAC-FACET

84

P. Muggli
MPI, Muenchen, Germany
E. Adli, S.J. Gessner, M.J. Hogan, S.Z. Li, M.D. Litos
SLAC, Menlo Park, California, USA
Y. Fang
USC, Los Angeles, California, USA
C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
N.C. Lopes, L.O. Silva, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal
O. Reimann
MPI-P, München, Germany

A self-modulated proton-driven plasma wakefield acceleration experiment is being designed at CERN and will occur within 3-5 years. Uncompressed 20GeV lepton bunches currently available at SLAC-FACET could be used to test key physics of the CERN experiment (e.g. self-modulation instability (SMI), SMI seeding, ion motion, hosing, differences between electrons (e-) and positrons (e+), etc)*. The E-209 collaboration was formed to carry SMI experiments at SLAC-FACET. Here we show through full-scale Osiris simulations that electron self-modulation grows and saturates in less than 10cm. Wakefield excitation in the blowout regime leads to acceleration gradients in excess of 20GeV/m. The self-modulated e^- bunch then sustains stable wakefields over meter-long plasmas. As a result, 7(12)GeV e^- energy gain(loss) could be observed. In the blowout regime, most of the wakefield phase defocuses e+. Thus, uncompressed e⁺ bunches drive lower acceleration gradients, but still in excess of 10GeV/m, over 1m of plasma. We will discuss the experimental setup, diagnostics to measure SMI (e.g. CTR, energy spectrometer, OTR, etc) and expected results. First experimental results may also be available.
*J. Vieira et al., Phys. Plasmas 19, 063105 (2012).

MOPAC47

Simulation of Laser Wakefield Acceleration in the Lorentz Boosted Frame with UPIC-EMMA

168

P. Yu, W. An, V.K. Decyk, W.B. Mori, F.S. Tsung
UCLA, Los Angeles, California, USA
R.A. Fonseca, L.O. Silva, J. Vieira
Instituto Superior Tecnico, Lisbon, Portugal
W. Lu, X.L. Xu
TUB, Beijing, People's Republic of China

Funding: Work supported by the US DoE under grants DE-SC0008491, DE-FG02-92- ER40727, DE-SC0008316 and DE-SC0007970, and by National Science Foundation under grants PHY-0936266, PHY-0960344 and PHY-0934856.
Simulation of laser wakefield accelerator (LWFA) in the Lorentz boosted frame, in which the laser and plasma spatial scales are comparable, can lead to computational time speed-ups to several orders of magnitude. In these simulation the relativistic drifting plasma inevitably induces a high frequency numerical instability. To reduce this numerical instability, we developed an EM-PIC code, UPIC-EMMA, based on the components of UCLA PIC framework (UPIC) which uses a spectral solver to advance the electromagnetic field in the Fourier space. With a low pass or "ring" filter implemented in the spectral solver, the numerical instability can be eliminated. In this paper we describe the new code, UPIC-EMMA, and present results from the code of LWFA simulation in the Lorentz boosted frame. These include the modeling cases where there are no self-trapped electrons, and modeling the self-trapped regime. Detailed comparison among Lorentz boosted frame results and lab frame results obtained from OSIRIS are given. We have used UPIC-EMMA to study LWFA in the self-guided regime to 100 GeV and good agreement was found with analytical scaling.