A5101526903- Laser-Plasma Interactions and Diagnostics
- Magnetic confinement fusion research
- Laser-induced spectroscopy and plasma
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Atomic and Molecular Physics
- Gamma-ray bursts and supernovae
- Laser-Matter Interactions and Applications
- Dust and Plasma Wave Phenomena
- Plasma Diagnostics and Applications
- Cold Fusion and Nuclear Reactions
- Astrophysics and Cosmic Phenomena
- Astro and Planetary Science
- Laser Design and Applications
- Astrophysics and Star Formation Studies
- Fusion materials and technologies
- Electron and X-Ray Spectroscopy Techniques
- Physics of Superconductivity and Magnetism
- Protein Interaction Studies and Fluorescence Analysis
- Nuclear reactor physics and engineering
- Superconducting Materials and Applications
- Pharmacological Effects of Natural Compounds
- Gold and Silver Nanoparticles Synthesis and Applications
- Electromagnetic Launch and Propulsion Technology
- Sports Dynamics and Biomechanics
University of Rochester
2010-2025
Energetics (United States)
2006-2024
Shenyang Pharmaceutical University
2023-2024
Hubei University
2023
University of California, Los Angeles
1999-2004
General Atomics (United States)
1997-1999
University of Wisconsin–Madison
1998-1999
Tsinghua University
1991-1992
The formation of strong, high Mach number (2-3), electrostatic shocks by laser pulses incident on overdense plasma slabs is observed in one- and two-dimensional particle-in-cell simulations, for a wide range intensities, pulse durations, target thicknesses, densities. propagate undisturbed across the plasma, accelerating ions (protons). For dimensionless field strength parameter a(0)=16 (Ilambda(2) approximately 3 x 10(20) W cm(-2) microm(2), where I intensity lambda wavelength), thicknesses...
Fermi acceleration is believed to be the primary mechanism produce high-energy charged particles in Universe, where gain energy successively from multiple reflections. Here, we present direct laboratory experimental evidence of ion energization single reflection off a supercritical collisionless shock, an essential component acceleration, laser-produced magnetized plasma. A quasi-monoenergetic beam with two four times shock velocity was observed, which consistent fast observed Earth’s bow...
This paper proposes a precision medical service system driven by big data. The PCA-GRA-BK algorithm, which combines principal component analysis (PCA), grey association (GRA) and Bayesian classifier (BK), is adopted. algorithm extracts critical information from massive data, identifies patient characteristics, predicts disease risk, provides personalized treatment plans. First, the uses PCA technology to reduce dimensionality of original data extract most representative components redundancy...
We have developed SpectaVla, a code that solves the multi-dimensional Vlasov–Maxwell equations using spectral method described in G. L. Delzanno [J. Comp. Phys. 301, 338 (2015)]. This is designed to take advantage of chip-scale tensor core optimized for 3D convolution with 8-bit fixed-point numbers. The benchmarked against theory on number fundamental plasma physics problems. employ rescaling and baseline shifting techniques ensure proper precision results when
Moringa oleifera leaves (MOL) are native to India and have high biological activities. To better understand the basic pharmacodynamic materials, chemical components in MOL their pharmacokinetic properties were studied quantitated using UPLC-Q-Exactive Orbitrap-MS. Forty-two compounds identified, including phenolic acids derivatives, flavonoids, isothiocyanates, nucleosides, alkaloids, other compounds. Two six flavonoids for UHPLC-MS/MS. Precision, accuracy, stability, matrix effects,...
Discharges with negative central magnetic shear (NCS) hold the promise of enhanced fusion performance in advanced tokamaks. However, stability to long wavelength magnetohydrodynamic modes is needed take advantage improved confinement found NCS discharges. The limits seen DIII-D [J. L. Luxon and G. Davis, Fusion Technol. 8, 441 (1985)] experiments depend on pressure current density profiles are good agreement calculations. a strongly peaked profile reach disruptive limit at low beta,...
Low Mach number, high beta fast mode shocks can occur in the magnetic reconnection outflows of solar flares. These shocks, which above flare loop tops, may provide electron energization responsible for some observed hard X-rays and contemporaneous radio emission. Here we present new two-dimensional particle-in-cell simulations low number/high quasi-perpendicular shocks. The show that electrons a certain energy threshold experience shock-drift-acceleration. transition between thermal...
Experiments have been conducted on the OMEGA EP laser facility to study effect of density scale length and overlapping beam geometry laser-plasma instabilities near below quarter-critical density. were in both planar (density L n ∼ 190 300 μm) spherical ( 150 with up four beams designed overlapped intensities lengths comparable experiments, but many fewer beams. In comparison previous experiments National Ignition Facility, it is confirmed that shorter favor two-plasmon decay (TPD)...
Quasi-parallel magnetized collisionless shocks are believed to be one of the most efficient accelerators in universe. Compared quasi-perpendicular shocks, quasi-parallel more difficult form laboratory and simulate because their large spatial scales long formation times. Our two-dimensional particle-in-cell simulations show that early stages shock achievable experiments planned for National Ignition Facility particles accelerated by diffusive acceleration (DSA) expected observable experiment....
The dynamics of two counter-streaming electron-positron-ion unmagnetized plasma shells with zero net charge is analyzed in the context magnetic field generation GRB internal shocks due to Weibel instability. effects large thermal motion particles, arbitrary mixture species and space are taken into account. We show that, although slow down instability, baryon loading leads a non-negligible growth rate even for temperatures different shell velocities, thus guaranteeing robustness occurrence...
This Letter examines the electron-hosing instability in relation to drivers of current and future plasma-wakefield experiments using fully three-dimensional particle-in-cell simulation models. The results are compared numerical solutions asymptotic idealized analytic equations. measured growth rates do not agree with existing theory behavior is shown depend sensitively on beam length, shape, charge. We find that even when severe hosing occurs wake can remain relatively stable.
Astrophysical shocks are often studied in the high Mach number limit but weakly compressive fast can occur magnetic reconnection outflows and considered to be a site of particle energization solar flares. Here we study microphysics such perpendicular, low collisionless using two-dimensional particle-in-cell (PIC) simulations with reduced ion/electron mass ratio employ moving wall boundary method for initial generation shock. This allows more control shock speed, smaller simulation box sizes,...
We derive an equation for energy transfer from relativistic charged particles to a cold background plasma appropriate finite-size that are used in particle-in-cell simulation codes. Expressions one-, two-, and three-dimensional presented, with special attention given the two-dimensional case. This is due electric field of wake set up by particle. The enhanced stopping dependent on q2/m, where q charge m mass particle, therefore macro-particles large but identical q/m will stop more rapidly....
Alfvén resonances, where the local flow speed relative to boundary is equal speed, introduce novel dynamical features in a differentially rotating plasma. The spatial structure and dynamics of current sheets such plasmas investigated analytically as well numerically. at resonances tend power-law singularities. growth algebraic time linear regime saturates presence dissipation without intervention nonlinear effects. These results have significant implications for forced reconnection wave...
A partial differential equation for a two-dimensional magnetohydrodynamic (MHD) equilibrium with flow and viscosity is derived. The used to describe the deformation of magnetic island caused by viscous drag sheared flow. characterized phase gradient perturbation across island. This has been observed experimentally in electron cyclotron emission data from DIII-D tokamak [J. L. Luxon G. Davis, Fusion Technol. 8, 441 (1985)].
The nonlinear and finite spot size effects for short laser pulses propagating in a plasma across constant magnetic field (ordinary extraordinary modes) have been studied. Starting from fluid Lagrangian magnetized plasmas with immobile ions, we derive the envelope equation also wake three-dimensional geometry. derived equations reveal that external reduces strength of ponderomotive self-focusing, causes astigmatic leads to possibility deflecting narrow pulse plasma.
Experimental observations suggest that toroidal plasma rotation can play a crucial role in determining the stability of tokamak. Conventional MHD analysis ignores rotation. Results from analytic and numerical number tokamak issues including are reported. Depending on profiles, net effect be either stabilizing or destabilizing; it also has substantial observed mode structure. Localized interchange, double kink mode, low-n resistive modes sheared magnetic island structure discussed.
Magnetic reconnection is commonly perceived to drive flow and particle acceleration in flares of solar, stellar, astrophysical disk coronae but the relative roles different mechanisms a given environment are not well understood. While outflow fast mode shocks have been predicted analytically, we show for first time via direct numerical simulations that such do indeed occur outflows when an obstacle present. These distinct from slow Petschek inflow shocks. If Fermi electrons operates weak...
The stability of general electron distribution functions to purely electromagnetic modes is considered, so as generalize the well-known analysis for bi-Gaussian functions. expansion an arbitrary nonrelativistic function into a modified version Hermite–Gaussian yields dispersion relation in compact form that depends on coefficients well plasma and its derivatives. enter depend only zeroth second moments from direction high temperature. solved analytically frequency low anisotropy (kinetic)...
A series of 2D in-plane plane wave particle-in-cell simulations find distinctive paths laser-plasma instability evolution in OMEGA-scale implosions, depending on the initial electron temperature. At low temperatures, two-plasmon decay (TPD) dominates both growth and steady state. high dominant modes switch to stimulated Raman scattering, but TPD still a state characterized by cavitation Langmuir turbulence. hot scaling is also obtained from that, when combined with laser/plasma conditions...
A multi-dimensional code FLAME-MD solving fluid-like laser-plasma instabilities' (LPIs) equations has been developed and is used to study multiple-beam two-plasmon decay (TPD) instability relevant a laser-entrance-hole window burn-off scenario in inertial confinement fusion (ICF) experiments. It found that TPD can be collectively driven by multiple beams incident at large incidence angles with respect the electron density gradient very low threshold. The polarization configuration of laser...
Two-dimensional particle-in-cell (PIC) simulations were performed for the cone-in-shell integrated fast-ignition experiments at Omega Laser Facility [W. Theobald et al., Phys. Plasmas 18, 056305 (2011)]. The initial plasma density profile in PIC was taken from hydrodynamic of prepulse interaction with gold cone. Hot-electron generation laser–pre-plasma interactions and transport up to 100× critical (nc) studied. simulation showed a mean divergence half-angle 68° 50% absorption hot electrons....
Perpendicular, magnetized, collisionless shocks in hydrogen and neon plasmas are studied with 2D particle-in-cell simulations for parameters accessible to experiments on OMEGA EP [Maywar et al., J. Phys.: Conf. Ser. 112, 032007 (2008)]. The performed realistic ion-electron mass ratios by which the relative importance of different micro-instabilities can be accurately captured. dispersion relation modified two-stream instability (MTSI), main dissipation mechanism these shocks, is used find...
The linear growth rate and saturation level of magnetic fields for Weibel instabilities driven by ion temperature anisotropy, defined as α=(T⊥∕T‖)−1 where T⊥ T‖ are temperatures perpendicular parallel to the wave vector, derived in small α limit. It is shown that ratio saturated energy initial scales fourth power electron mass ratio, m∕M, an initially unmagnetized plasma with α≤M∕m. Particle-in-cell simulations confirm scaling also show gain same order magnitude field energy. This implies...