W. Rozmus

University of Alberta

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V. Yu. Bychenkov

P.N. Lebedev Physical Institute of the Russian Academy of Sciences

112

C. E. Capjack

University of Alberta

A. V. Brantov

P.N. Lebedev Physical Institute of the Russian Academy of Sciences

V. T. Tikhonchuk

Université de Bordeaux

M. Sherlock

Lawrence Livermore National Laboratory

G. F. Swadling

Lawrence Livermore National Laboratory

S. H. Glenzer

SLAC National Accelerator Laboratory

D. Pesme

École Polytechnique

C. Bruulsema

Lawrence Livermore National Laboratory

R. Fedosejevs

University of Alberta

Cooperative Institutions

Lawrence Livermore National Laboratory

186

University of Alberta

104

University of Rochester

Energetics (United States)

Imperial College London

Centre National de la Recherche Scientifique

Los Alamos National Laboratory

General Atomics (United States)

University of Michigan–Ann Arbor

École Polytechnique

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THE TIME DEPENDENT TRANSPORT COEFFICIENT FOR THE TWO-COMPONENT PLASMA

Le Journal de Physique Colloques (1979)

W. Rozmus

Component (thermodynamics)

10.1051/jphyscol:19797254

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Citations (0)

Numerical study of effects of cellular nanostructure on scattered light

C. Liu C. E. Capjack W. Rozmus Kirat Pal Singh C. Backhouse

A three dimensional code for solving the set of Maxwell equations with the finite-difference time-domain method is developed to simulate the propagation and scattering of light in biological cells for realistic conditions. The numerical techniques employed in this code include the Yee algorithm, the absorbing boundary conditions, the total-field/scattered-field formulation, the discrete Fourier transformation and the near-to-far field transform with the equivalent electric and magnetic currents. The code is capable of simulating light scattering from cells with complex internal nanostructures at all angles. The effects of cellular nanostructure on the scattered light are studied. It is shown that changes in cellular nanostructures could cause significant changes in the scattered light at particular angles.

10.1109/icmens.2003.1221984

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Citations (2)

Theory of filamentation instability and stimulated Brillouin scattering with nonlocal hydrodynamics

Physics of Plasmas (2000)

V. Yu. Bychenkov W. Rozmus A. V. Brantov V. T. Tikhonchuk

A linear theory of stimulated Brillouin scattering and filamentation instabilities has been formulated using nonlocal transport equations for a laser heated plasma, resulting in a model which is fully equivalent to a linearized kinetic description. The inverse-Bremsstrahlung heating, nonlocal energy redistribution, and ponderomotive laser–plasma interactions are correctly taken into account contributing to a new generalized driving force for these instabilities. Temporal and spatial growth rates, thresholds and dominant perturbation wavelengths are obtained. This theory predicts substantial modifications of the ponderomotive results for conditions relevant to many laser plasma interaction experiments. A new nonlocal and nonlinear model of laser propagation in weakly collisional plasmas has been derived.

Filamentation

Ponderomotive force

10.1063/1.873970

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Citations (33)

Stimulated Raman backscattering in the presence of ion-acoustic fluctuations

The Physics of Fluids (1983)

W. Rozmus A. A. Offenberger R. Fedosejevs

Threshold conditions are analyzed for stimulated Raman backscattering (SRS) from an underdense plasma in the presence of ion-acoustic fluctuations. For typical ion-acoustic spectra which could result from a Brillouin instability occurring simultaneously with SRS, a reduced collisional threshold due to induced bremsstrahlung is found for the Raman instability. Similarly, for inhomogeneous plasma the phase mismatch created by a density gradient can be compensated for by an inhomogeneity in the ion-acoustic spectrum; as a consequence, the inhomogeneity threshold for absolute instability can be substantially reduced. Comparisons are made with experimental observations of stimulated Raman scattering in the presence of strong stimulated Brillouin scattering for CO2 laser-plasma interaction. It is found theoretically that for fluctuation levels typical of that accompanying SBS, induced bremsstrahlung growth rates for Langmuir waves can be of the order of collisional damping rates.

Brillouin zone

Ion acoustic wave

10.1063/1.864219

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Citations (33)

A microfluidic device with on-chip optical waveguide interrogation of individual biological cells for medical diagnostics

Kamal Deep Singh C. Liu C. E. Capjack W. Rozmus C. Backhouse

We present a microfluidic device for on-chip optical analysis and characterisation of biological cells. We employ a novel waveguiding technique for detection and analysis of the cells. This waveguiding technique is particularly well suited to this since a number of unique characteristics of the optical waveguide come together to enable detailed analysis of the very low level of scattered light. We are interested in the analysis and characterisation of sub-wavelength features such as nuclei and mitochondria within living cells. Such nanoscale probing of intracellular matter promises to offer reliable diagnostic procedures for biological cells. Of particular interest are the mitochondria, since the size and number of these can provide useful information as to the health of the cell. Mitochondria are the organelles in which energy production takes place, and as such are of vital importance. Mitochondrial abnormalities are often associated with serious diseases including cancer.

Microfluidic chip

Waveguide

Organelle

Lab-on-a-Chip

10.1109/icmens.2003.1222026

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Citations (3)

Picosecond Thermodynamics in Underdense Plasmas Measured with Thomson Scattering

Physical Review Letters (2019)

Andrew Davies D. Haberberger J. Katz S. Bucht J. P. Palastro

The rapid evolutions of the electron density and temperature in a laser-produced plasma were measured using collective Thomson scattering. Unprecedented picosecond time resolution, enabled by a pulse-front-tilt compensated spectrometer, revealed a transition in the plasma-wave dynamics from an initially cold, collisional state to a quasistationary, collisionless state. The Thomson-scattering spectra were compared with theoretical calculations of the fluctuation spectrum using either a conventional Bhatnagar-Gross-Krook (BGK) collision operator or the rigorous Landau collision terms: the BGK model overestimates the electron temperature by 50% in the most-collisional conditions.

Thomson scattering

Picosecond

Collision frequency

Electron temperature

10.1103/physrevlett.122.155001

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Citations (13)

Plasmadynamical description of two-component weakly coupled plasma

Journal of Plasma Physics (1980)

W. Rozmus

Plasmadynamical equations for a two-component plasma are obtained starting from the linearized Vlasov–Landau kinetic equation. Explicit formulae are given for the frequency dependent transport coefficients. Eigenvalues of ten plasmadynamical modes are also discussed.

Vlasov Equation

Component (thermodynamics)

Plasma Modeling

Landau damping

10.1017/s0022377800022820

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Citations (2)

Self- Focusing and Channeling of Relativistic Laser Pulses in Underdense Plasmas

Bulletin of the American Physical Society (2009)

N. Naseri W. Rozmus

Self-focusing

Relativistic plasma

Source

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Label-free and noninvasive optical detection of the distribution of nanometer-size mitochondria in single cells

Journal of Biomedical Optics (2011)

Xuantao Su Yuanyuan Qiu Leah A. Marquez‐Curtis Manisha Gupta C. E. Capjack

A microfluidic flow cytometric technique capable of obtaining information on nanometer-sized organelles in single cells in a label-free, noninvasive optical manner was developed. Experimental two-dimensional (2D) light scattering patterns from malignant lymphoid cells (Jurkat cell line) and normal hematopoietic stem cells (cord blood CD34+ cells) were compared with those obtained from finite-difference time-domain simulations. In the simulations, we assumed that the mitochondria were randomly distributed throughout a Jurkat cell, and aggregated in a CD34+ cell. Comparison of the experimental and simulated light scattering patterns led us to conclude that distinction from these two types of cells may be due to different mitochondrial distributions. This observation was confirmed by conventional confocal fluorescence microscopy. A method for potential cell discrimination was developed based on analysis of the 2D light scattering patterns. Potential clinical applications using mitochondria as intrinsic biological markers in single cells were discussed in terms of normal cells (CD34+ cell and lymphocytes) versus malignant cells (THP-1 and Jurkat cell lines).

Jurkat cells

Organelle

Single-Cell Analysis

10.1117/1.3583577

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Citations (27)

Temperature scaling of hot electrons produced by a tightly focused relativistic-intensity laser at 0.5 kHz repetition rate

Applied Physics Letters (2010)

Aghapi Mordovanakis P. E. Masson-Laborde James Easter Konstantin Popov Bixue Hou

The energy spectrum of hot electrons emitted from the interaction of a relativistically intense laser with an Al plasma is measured at a repetition rate of 0.5 kHz by accumulating ∼103 highly reproducible laser shots. In the 1017–2×1018 W/cm2 range, the temperature of electrons escaping the plasma along the specular direction scales as (Iλ2)0.64±0.05 for p-polarized pulses incident at 45°. This scaling is in good agreement with three-dimensional particle-in-cell simulations and a simple model that estimates the hot-electron temperature by considering the balance between the deposited laser intensity and the energy carried away by those electrons.

Electron temperature

Intensity

10.1063/1.3306730

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Citations (33)