PAC2013 - List of Authors (Fonseca, R.A.)

Paper	Title	Page
MOPAC39	Self and Ionization-Injection in LWFA for Near Term Lasers	150
	A.W. Davidson, C. Joshi, W. Lu, W.B. Mori UCLA, Los Angeles, California, USA R.A. Fonseca, J.L. Martins, L.O. Silva Instituto Superior Tecnico, Lisbon, Portugal M. Zeng Tsinghua University, Beijing, People's Republic of China
	Funding: Supported by the US Department of Energy under DE-SC0008491, DE-FG02-92- ER40727, DE-SC0008316 and DE-SC0007970, and the National Science Foundation under PHY- 0936266, PHY-0960344 and PHY-0934856. In plasma based accelerators (LWFA and PWFA), the methods of injecting high qual- ity electron bunches into the accelerating wakeﬁeld is of utmost importance for various applications. Ionization injection has received much recent attention in experiments, in theory, and in simulation. Here we use 3D OSIRIS simulations to investigate generating high quality electron beams generated through ionization injection. This includes the study of two-stage ionization injected LWFA in the self-guided regime. The ﬁrst, i.e., injection, stage is a mixture of 99.5% He and 0.5% N gasses, while the second, i.,e., acceleration stage is entirely composed of He. Laser intensities from 100TW to 1 PW will be modeled. In the 500TW case, energies greater than 3 GeV with 5% energy spread were observed.

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

Self and Ionization-Injection in LWFA for Near Term Lasers

150

A.W. Davidson, C. Joshi, W. Lu, W.B. Mori
UCLA, Los Angeles, California, USA
R.A. Fonseca, J.L. Martins, L.O. Silva
Instituto Superior Tecnico, Lisbon, Portugal
M. Zeng
Tsinghua University, Beijing, People's Republic of China

Funding: Supported by the US Department of Energy under DE-SC0008491, DE-FG02-92- ER40727, DE-SC0008316 and DE-SC0007970, and the National Science Foundation under PHY- 0936266, PHY-0960344 and PHY-0934856.
In plasma based accelerators (LWFA and PWFA), the methods of injecting high qual- ity electron bunches into the accelerating wakeﬁeld is of utmost importance for various applications. Ionization injection has received much recent attention in experiments, in theory, and in simulation. Here we use 3D OSIRIS simulations to investigate generating high quality electron beams generated through ionization injection. This includes the study of two-stage ionization injected LWFA in the self-guided regime. The ﬁrst, i.e., injection, stage is a mixture of 99.5% He and 0.5% N gasses, while the second, i.,e., acceleration stage is entirely composed of He. Laser intensities from 100TW to 1 PW will be modeled. In the 500TW case, energies greater than 3 GeV with 5% energy spread were observed.

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.