A5016664197- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- Particle accelerators and beam dynamics
- Magnetic confinement fusion research
- Particle Accelerators and Free-Electron Lasers
- High-pressure geophysics and materials
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Laser Design and Applications
- Pulsed Power Technology Applications
- Gyrotron and Vacuum Electronics Research
- Ion-surface interactions and analysis
- Advanced X-ray Imaging Techniques
- Solar and Space Plasma Dynamics
- Advanced Fiber Laser Technologies
- Spectroscopy and Laser Applications
- Solid State Laser Technologies
- Particle Detector Development and Performance
- Dust and Plasma Wave Phenomena
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Laser Material Processing Techniques
- Photocathodes and Microchannel Plates
- Quantum optics and atomic interactions
University of California, Los Angeles
2014-2024
Tsinghua University
2021
Institute of Atomic and Molecular Sciences, Academia Sinica
2021
National Central University
2021
National Taiwan University
2021
University of Rochester
2020
Energetics (United States)
2020
SLAC National Accelerator Laboratory
2009-2020
Lawrence Livermore National Laboratory
1988-2020
Lawrence Berkeley National Laboratory
2020
The extraordinary ability of space-charge waves in plasmas to accelerate charged particles at gradients that are orders magnitude greater than current accelerators has been well documented. We develop a phenomenological framework for laser wakefield acceleration (LWFA) the 3D nonlinear regime, which plasma electrons expelled by radiation pressure short pulse laser, leading nearly complete blowout. Our theory provides recipe designing LWFA given and parameters estimates number energy...
The concepts of matched-beam, self-guided laser propagation and ionization-induced injection have been combined to accelerate electrons up 1.45 GeV energy in a wakefield accelerator. From the spatial spectral content light exiting plasma, we infer that 60 fs, 110 TW pulse is guided excites wake over entire 1.3 cm length gas cell at densities below $1.5\ifmmode\times\else\texttimes\fi{}{10}^{18}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$. High-energy are observed only when small (3%)...
Abstract Plasma-based accelerators use the strong electromagnetic fields that can be supported by plasmas to accelerate charged particles high energies. Accelerating field structures in plasma generated powerful laser pulses or particle beams. This research has recently transitioned from involving a few small-scale efforts development of national and international networks scientists substantial investment large-scale infrastructure. In this New Journal Physics 2020 Plasma Accelerator...
The relativistic plasma wave excited when the frequency difference between two copropagating C${\mathrm{O}}_{2}$ laser beams equals is detected for first time. plasma-wave frequency, number, spatial extent, and saturation time are directly measured by use of 7-mrad, collective, ruby Thomson scattering forward-scattered ir spectrum. amplitude $\frac{\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{n}}{{n}_{0}}$ inferred to be (1-3)% which gives a longitudinal electric field 0.3 1 GV/m at intensity...
A plasma-wakefield accelerator has accelerated particles by over 2.7 GeV in a 10 cm long plasma module. 28.5 electron beam with 1.8 x 10(10) electrons is compressed to 20 microm longitudinally and focused transverse spot size of at the entrance column lithium vapor density 2.8 10(17) atoms/cm3. The bunch fully ionizes create then expels electrons. These return one-half period later driving large amplitude wake that turn accelerates back more than GeV.
The first three-dimensional, particle-in-cell (PIC) simulations of laser-wakefield acceleration self-injected electrons in a 0.84 cm long plasma channel are reported. frequency evolution the initially 50 fs (FWHM) laser pulse by photon interaction with wake followed dispersion enhances which eventually leads to self-injection from wall. This bunch remains spatially highly localized. Its phase space rotation due slippage respect monoenergetic central energy 0.26 GeV after 0.55 propagation. At...
Finite-beam, two-dimensional particle simulations of single- and double-frequency laser-plasma heating are presented. In the single-frequency case, Raman backscatter side scatter initially heat plasma. Even in absence strong forward scattering, subsequent electron is observed. When two collinear laser beams with $\ensuremath{\Delta}\ensuremath{\omega}={\ensuremath{\omega}}_{p}$ used, a coherent plasma wave heats electrons to many megaelectronvolts. latter ion dynamics eventually disrupts process.
This article first gives the authors' perspectives on how field of plasma-based acceleration (PBA) developed and current experiments, theory, simulations are motivated by long term applications PBA to a future linear collider an x-ray free electron laser. We then focus some early that will likely emerge from research such as beam radiotherapy, directional but incoherent beams for science technology, near single cycle continuously tunable infrared pulses spectroscopy, non-perturbative quantum...
The propagation of an intense, subpicosecond laser pulse through a substantial length $(L/\ensuremath{\lambda}\ensuremath{\sim}{10}^{3})$ underdense plasma $({n/n}_{c}\ensuremath{\sim}1%)$ is studied experiments and computer simulations. For $I\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}8\ifmmode\times\else\texttimes\fi{}{10}^{17}$ W/c${\mathrm{m}}^{2}$ only 55% the incident light was transmitted within focal cone angle. decrease in transmission accompanied by Raman forward scattering...
Since its inception in the early 1980s, field of plasma-based particle accelerators has made remarkable advances. Robust plasma accelerating structures can now be excited over centimeter scales using short laser pulses and meter ultrarelativistic beams. Accelerating fields excess tens GV/m sustained these lengths. Laser-driven routinely produce monoenergetic, low divergence electron beams 100MeV–1GeV range, whereas electron-beam driven have demonstrated ability to double energy 42GeV...
Hot electron generation in a long-density-scale-length (\ensuremath{\sim}300 \ensuremath{\mu}m) underdense plasma has been studied. For of maximum density $\frac{1}{4}{n}_{c}$ the hot emission is localized plane polarization incident C${\mathrm{O}}_{2}$ laser and peaked about 45\ifmmode^\circ\else\textdegree\fi{} with respect to $\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}$ vector beam, both forward backward directions. These observations suggest that electrons are generated by...
In this article we review the prospects of laser wakefield accelerators as next generation light sources for applications. This work arose a result discussions held at 2013 Laser Plasma Accelerators Workshop. X-ray phase contrast imaging, x-ray absorption spectroscopy, and nuclear resonance fluorescence are highlighted potential applications laser–plasma based sources. We discuss ongoing future efforts to improve properties radiation from plasma betatron emission Compton scattering using...
During the past two decades of research, ultra-relativistic beam-driven plasma wakefield accelerator (PWFA) concept has achieved many significant milestones. These include demonstration ultra-high gradient acceleration electrons over meter-scale structures, efficient a narrow energy spread electron bunch at high-gradients, positron using wakes in uniform plasmas and hollow channels, demonstrating that highly nonlinear 'blow-out regime' have electric field structure necessary for preserving...
The successful utilization of an ion channel in a plasma to wiggle 28.5-GeV electron beam obtain broadband x-ray radiation is reported. induced by the bunch as it propagates through underdense 1.4-meter-long lithium plasma. quadratic density dependence spontaneously emitted betatron and divergence angle approximately (1-3)x10(-4) radian forward-emitted x-rays consequence motion are good agreement with theory. absolute photon yield peak spectral brightness at 14.2-keV energy estimated.
In 2004, using a 3D particle-in-cell (PIC) model [F. S. Tsung et al., Phys. Rev. Lett. 93, 185004 (2004)], it was predicted that 16.5TW, 50fs laser propagating through nearly 0.5cm of 3×1018cm−3 preformed plasma channel would generate monoenergetic bunch electrons with central energy 240MeV after propagation. addition, out to 840MeV were seen if the propagated 0.8cm same plasma. The simulations showed self-injection occurs intensity increases due combination photon deceleration, group...
An intense, high-energy electron or positron beam can have focused intensities rivaling those of today’s most powerful laser beams. For example, the 5 ps (full-width, half-maximum), 50 GeV at Stanford Linear Accelerator Center (SLAC) 1 kA and to a 3 micron rms spot size gives >1020 W/cm−2 repetition rate >10 Hz. Unlike fs pulse which interacts with surface solid target, particle readily tunnel through tens cm steel. However, same be manipulated quite effectively by plasma that...
The self-guiding of relativistically intense but ultrashort laser pulses has been experimentally investigated as a function power, plasma density, and length in the blowout regime. extent self-guiding, observed by imaging exit, is shown to be limited nonlinear pump depletion with over tens Rayleigh lengths. Spectrally resolved images exit show evidence consistent wake. Minimal losses self-guided pulse resulted when initial spot size was matched radius.
Progress on developing a plasma amplifier/compressor based stimulated Raman scattering of nanosecond laser pulses is reported. Generation millijoule seed pulse at wavelength that redshifted relative to the pump beam has been achieved using an external gas cell. By interacting shifted picosecond and in jet density ∼1019 cm−3, upper limit intensity avoid angular spray amplified determined. The amplification studied as function intensities. Although heating by results strong Landau damping...
An electron beam has gained a maximum energy of 9 GeV per particle in 1.3 m-long beam-driven plasma wakefield accelerator. The amount charge accelerated the spectral peak was 28.3 pC, and root-mean-square spread 5.0%. mean gain 215 shot data set 115 pC 5.3 GeV, respectively, corresponding to an acceleration gradient 4.0 GeV/m at peak. 5.1%. These results are consistent with extrapolation previously reported using shorter, 36 cm-long source within 10%, evincing non-evolving wake structure...
Collisionless shock acceleration of protons and ${\mathrm{C}}^{6+}$ ions has been achieved by the interaction a ${10}^{20}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$, $1\text{ }\ensuremath{\mu}\mathrm{m}$ laser with near-critical density plasma. Ablation initially solid target secondary allows for systematic control plasma profile. This enables production beams peaked spectra energies $10--18\text{ }\mathrm{MeV}/\mathrm{amu}$ energy spreads 10%--20% up to...
An x-ray source generated by an electron beam produced using a Self-Modulated Laser Wakefield Accelerator (SM-LWFA) is explored for use in high energy density science facilities. By colliding the beam, with maximum of 380 MeV, total charge >10 nC and divergence 64 × 100 mrad, from SM-LWFA driven 1 ps 120 J laser, into high-Z foil, x/gamma-ray was generated. A broadband bremsstrahlung spectrum temperatures ranging 0.8 to 2 MeV measured almost orders magnitude flux increase when compared other...
Cavity-free lasing in atmospheric air has stimulated intense research toward a fundamental understanding of underlying physical mechanisms. In this Letter, we identify new mechanism-a third-harmonic photon mediated resonant energy transfer pathway leading to population inversion argon via an initial three-photon excitation nitrogen molecules irradiated by 261 nm pulses-that enables bidirectional two-color cascaded air. By making pump-probe measurements, conclusively show that such results...