Bulletin of the American Physical Society
61st Annual Meeting of the APS Division of Plasma Physics
Volume 64, Number 11
Monday–Friday, October 21–25, 2019; Fort Lauderdale, Florida
Session NI3: AB Invited: Particle Acceleration, Beams, and Relativistic Plasmas |
Hide Abstracts |
Chair: Stefan Karsch, Max-Planck Institute for Quantum Optics Room: Floridian Ballroom CD |
Wednesday, October 23, 2019 9:30AM - 10:00AM |
NI3.00001: Laser-Driven Plasma-Based Sources of Intense, Ultrafast, and Coherent Radiation Invited Speaker: Matthew Edwards Extreme light sources - providing attosecond pulse durations, ultra-relativistic intensities, or x-ray wavelengths - allow us to probe the boundaries of modern physics with exquisite precision and unrivaled power. Future source development requires plasmas, which support high-intensity fields, offer useful non-linear and ultrafast responses, and scale with wavelength. We focus on two plasma-based mechanisms suitable for the near-infrared to soft-x-ray spectral window: relativistic high-order harmonic generation for high-power frequency conversion and parametric plasma amplification using stimulated Raman or Brillouin scattering. For both mechanisms efficiency is crucial, and, drawing on similar analytic and computational tools, we show how simple models lead to efficiency limits. For high-order harmonic generation, paths to the highest efficiencies can be found by manipulating the laser waveform or plasma parameters [Edwards et al. Opt. Lett. 39 (2014); Edwards and Mikhailova, PRA 93 (2016); Edwards and Mikhailova, PRL 117 (2016)]. For plasma amplification, efficiency can be improved via use of an appropriate scattering mechanism for the specific wavelength and conditions [Edwards et al. PoP 23 (2016); Edwards et al. PRE 96 (2017); Edwards et al. PRL (2019)], tuning of plasma properties [Edwards et al. PoP 22 (2015)], and the suppression of competing instabilities [Edwards et al. PoP 24 (2017)]. We explore physics-based and engineering solutions for improving performance - informed by applications [Edwards et al. PRL 116 (2016)] and alternative mechanisms [Edwards et al. PoP 25 (2018)] - and relate these processes to the broader ecosystem of plasma and non-plasma sources of extreme radiation. [Preview Abstract] |
Wednesday, October 23, 2019 10:00AM - 10:30AM |
NI3.00002: Interactions between relativistic non-linear plasma waves driven by laser pulses at highest intensities. Invited Speaker: Grigory Golovin Thanks to recent advances in powerful ultrashort laser systems we can now drive relativistic non-linear plasma waves and use them to capture and accelerate electrons to ultra-relativistic energies. The field of laser-wakefield acceleration is showing tremendous progress with a lot of research around the world focused on developing new ways to trap electrons in plasma waves to optimize the quality of the accelerated beams. The key to success is a precise control over the phase at which the trapping occurs and, at the same time, minimization of its duration. We have recently developed [1] a novel trapping method which relies on the use of two laser pulses each driving its own non-linear wake. The pulses and their wakes intersect and interact, resulting in controlled trapping of free plasma electrons into both wakes. The delay between the pulses allows to precisely control the trapping phase; the trapping also occurs in the limited overlap region, which minimizes energy spread of the generated electron beams. Due to periodicity of wake-wake interference process, periodic trapping can be achieved, and an ultrashort bunch train can be generated, which can greatly reduce deleterious effects of beam loading and space charge. This novel approach to controlled trapping can be also used to study properties of the participating non-linear plasma wakes since the trapped and accelerated electrons carry information on electron momentum distribution in the area of the wake overlap. [1] G. Golovin, W. Yan, J. Luo, C. Fruhling, D. Haden, B. Zhao, C. Liu, M. Chen, S. Chen, P. Zhang, S. Banerjee, and D. Umstadter, Phys. Rev. Lett. 121, 104801 (2018). [Preview Abstract] |
Wednesday, October 23, 2019 10:30AM - 11:00AM |
NI3.00003: Petawatt laser guiding and electron beam acceleration to 8 GeV in laser-heated capillary discharge waveguides Invited Speaker: Anthony Gonsalves In order to take advantage of the large acceleration gradients in laser plasma accelerators and achieve high beam energies, preformed plasma waveguides can be used to mitigate laser diffraction of focused laser pulses, which increases the acceleration length and the energy gain for a given laser power. Here we report on guiding of relativistically intense laser pulses with PW peak power over 15 diffraction lengths by increasing the focusing strength of a capillary discharge waveguide using laser inverse Bremsstrahlung heating. This allowed production of electron beams with quasi-monoenergetic peaks in energy up to 7.8 GeV [1], almost double what was previously demonstrated [2]. [1] A.J. Gonsalves et al. Phys. Rev. Lett. 122, 08401 (2019) [2] W. P. Leemans et al., Phys. Rev. Lett. 113, 245002 (2014) [Preview Abstract] |
Wednesday, October 23, 2019 11:00AM - 11:30AM |
NI3.00004: Optimizing Direct Laser Acceleration Invited Speaker: Amina Hussein For high-intensity, sustained laser-plasma interactions, the laser pulse will ponderomotively expel nearly all of the electrons within its focal volume, creating a positively charged plasma channel. This channel is slowly evolving relative to the timescale of electron motion. Electrons that become trapped in this channel can gain longitudinal momentum from the laser field through the $v \times B$ force in the Lorentz force equation. This process is known as Direct Laser Acceleration (DLA). Experiments performed at the OMEGA EP laser facility have demonstrated DLA of electrons up to 600 MeV from a low-density plasma target using a high-energy, picosecond duration pulse at an optimal plasma density. High energy electrons beams with nearly 100 nC charge were also produced. Two-dimensional particle-in-cell (PIC) simulations conducted using the EPOCH code confirm DLA as the dominant acceleration mechanism and elucidate that dynamic role of quasi-static channel fields on electron energy enhancement. PIC simulations also indicate that longer pulse duration could be used to produce higher charge electron beams by DLA. Particle tracking shows considerable acceleration and deceleration of electrons and indicates that this process could be an efficient source of hard X-rays with the capability to be accurately synchronized to short pulse laser-initiated events. [Preview Abstract] |
Wednesday, October 23, 2019 11:30AM - 12:00PM |
NI3.00005: Self-Modulated Laser Wakefield Acceleration for OMEGA EP Invited Speaker: Jessica Shaw Self-modulated laser wakefield accelerators (SM-LWFA's) driven by picosecond-scale, kilojoule-class lasers enable particle beams and x-ray sources that could be coupled to experiments driven by large-scale, high-energy lasers such as the OMEGA laser at the Laboratory for Laser Energetics (LLE) or the National Ignition Facility at Lawrence Livermore National Laboratory. We report on the development of a SM-LWFA platform for the OMEGA EP Laser System at LLE. To provide the underdense plasma targets required for SM-LWFA, a new gas-jet system for OMEGA and OMEGA EP has been fielded and characterized. The focal length of OMEGA EP has been extended to larger $f$ numbers to generate laser focal geometries well suited to SM-LWFA. Initial experiments demonstrated electron beams with electron energies exceeding 200 MeV, divergences as low as 40 mrad, and charge exceeding 100 nC. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0003856, the Department of Energy under Award Number DE-SC0017950, and the National Science Foundation under Award Number PHY{\-}1705224. *In collaboration with F. Albert, N. Lemos, P. M. King, M. A. Romo-Gonzalez, J.~P. Palastro, and D. H. Froula. [Preview Abstract] |
Wednesday, October 23, 2019 12:00PM - 12:30PM |
NI3.00006: Collisionless Shock Wave Acceleration of Narrow Energy Spread Ion Beams Using Ultraintense 1 \textmu m Lasers Invited Speaker: Sergei Tochitsky The quest for a compact laser-based source of high energy and mono-energetic proton beams is an active field of research. Such a source can have a high impact in many applications such as injectors for traditional linear accelerators, high precision measurements of field structures and potentially allow for the broadening of access to treatments with high societal impact. Traditionally, laser produced beams of ions have been generated using the TNSA mechanism, which produces a continuous exponentially decreasing spectrum with cut off energies limited to \textasciitilde 100 MeV using current laser systems. This work overviews our experimental and numerical results on production of narrow energy spread beams from acceleration via a different mechanism electrostatic collisionless shockwave driven in near critical density plasmas by 1 \textmu m wavelength lasers.~Shock waves driven by high intensity 1 \textmu m wavelength laser systems in CH targets produced beams of protons with peak energies of 10-45 MeV and narrow energy spreads of 10-35{\%}.~ The number of protons within the narrow distribution was observed to be up to \textasciitilde 1x10\textasciicircum 9, a 10\textasciicircum 4X increase over our previous work when using 10 \textmu m wavelength laser systems. Coincident with these proton beams was the observation of a narrow distribution of C$^{\mathrm{6+}}$~ions that were accelerated to a similar velocity as the proton beam consistent with acceleration by the moving potential of a shock wave. Particle-in-cell simulations show shock accelerated beams with narrow energy distributions of ions consistent with the experiments. Simulations also indicate the plasma profile determines the trade-off between the beam charge and energy and that with additional target optimization narrow energy spread beams exceeding 100 MeV/amu can be produced using the currently available laser systems. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700