A5072880658- Plasma Diagnostics and Applications
- Plasma Applications and Diagnostics
- Laser-induced spectroscopy and plasma
- Plasma and Flow Control in Aerodynamics
- Laser Design and Applications
- Laser-Matter Interactions and Applications
- Electrohydrodynamics and Fluid Dynamics
- Spectroscopy and Laser Applications
- Gas Dynamics and Kinetic Theory
- Atomic and Molecular Physics
- Laser-Plasma Interactions and Diagnostics
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Fiber Laser Technologies
- Combustion and flame dynamics
- Computational Fluid Dynamics and Aerodynamics
- Lightning and Electromagnetic Phenomena
- Mass Spectrometry Techniques and Applications
- Aerosol Filtration and Electrostatic Precipitation
- Dust and Plasma Wave Phenomena
- Ionosphere and magnetosphere dynamics
- Fluid Dynamics and Turbulent Flows
- Magnetic and Electromagnetic Effects
- Laser-Ablation Synthesis of Nanoparticles
- Vacuum and Plasma Arcs
- Atomic and Subatomic Physics Research
Princeton University
2016-2025
University of California, San Diego
2023
Manufacturing Advocacy & Growth Network (United States)
2023
Institute for Problems in Mechanics
1992-2022
Princeton Plasma Physics Laboratory
2015-2022
Texas A&M University
2011-2022
Texas A&M University – Kingsville
2022
University of Liverpool
2022
Luxembourg Institute of Science and Technology
2022
Moscow Institute of Physics and Technology
2021
A detailed physical model for asymmetric dielectric barrier discharge (DBD) in air at low voltages (1.5–2 kV) is developed. Modeling of DBD with an applied sinusoidal voltage carried out two dimensions. The leading role charging the surface by electrons cathode phase shown to be critical, acting as a harpoon that pulls positive ions forward and accelerates gas anode phase. ion motion back toward exposed electrode major source inefficiency or near-sinusoidal cases. Based on understanding...
We report an experimental proof and full characterization of laser generation in molecular nitrogen argon-nitrogen gas mixture remotely excited at a distance above 2 m femtosecond filament. Filamentation experiments performed with near-infrared, 1-\ensuremath{\mu}m-wavelength midinfrared, 4-\ensuremath{\mu}m-wavelength short-pulse sources show that mid-IR pulses enable radical enhancement filamentation-assisted lasing by N${}_{2}$ molecules. Energies as high 3.5 \ensuremath{\mu}J are...
We study the cooling of a dielectric nanoscale particle trapped in an optical cavity. derive frictional force for motion cavity field and show that rate is proportional to square oscillation amplitude frequency. Both radial axial components center-of-mass particle, which are coupled by field, cooled. This analogous two but damped pendulums. Our simulations nanosphere can be cooled ${e}^{\ensuremath{-}1}$ its initial momentum over time scales hundredths milliseconds.
We present quantitative schlieren measurements and numerical analyses of the thermal hydrodynamic effects a nanosecond repetitively pulsed (NRP) discharge in atmospheric pressure air at 300 1000 K. The plasma is created by voltage pulses an amplitude 10 kV duration ns, applied frequency 1–10 kHz between two pin electrodes separated 2 or 4 mm. electrical energy each pulse order 1 mJ. recorded single-shot images starting from 50 ns to 3 µs after discharge. time-resolved show shock-wave...
Abstract Manipulating surface charge, electric field, and plasma afterglow in a non-equilibrium is critical to control plasma-surface interaction for catalysis manufacturing. Here, we show enhancements of field during breakdown, by ferroelectric barrier discharge. The results that the ferroelectrics manifest spontaneous polarization increase charge two orders magnitude compared discharge with an alumina barrier. Time-resolved in-situ measurements reveal fast enhances breakdown streamer...
Minimization of the power required to sustain weakly ionized plasmas can be achieved if energy ionizing electrons is high, from tens thousands electronvolts. These spend about a half their on ionization cascades, in contrast low-energy (1-3 eV) conventional discharges that dissipate most nonionizing inelastic collisions. High-energy injected into gas as beams. Alternatively, they created situ by applying very strong electric field for short time, with repetition rate matching recombination....
The possibility of controlling scramjet inlets in off-design conditions by operating a near-surface magnetohydrodynamic (MHD) system upstream the inlet is examined. required electrical conductivity air supposed to be created electron beams injected into from vehicle along magnetic field lines. A simple model beam-generated ionization profile developed and coupled with plasma kinetics, MHD equations, two-dimensional inviscid flow equations. Calculations show that an reasonable parameters...
The focus of this work is on theoretical analysis fundamental aspects high-speed flow control using electric and magnetic fields. principal challenge that the relatively cold gas weakly ionized in discharges or by electron beams, with ionization fraction ranging from 10 −8 to −5 . low means that, although electrons ions can interact electromagnetic fields, transfer momentum energy bulk neutral be quite inefficient. Analytical estimates show even at highest values field exist cathode sheaths...
Experimental studies were conducted of a flow induced in an initially quiescent room air by single asymmetric dielectric barrier discharge driven voltage waveforms consisting repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal square-wave bias voltage. To characterize the and to optimize their matching plasma, numerical code for short pulse calculations with arbitrary impedance load was developed. A new approach nonintrusive diagnostics plasma actuator...
We present an experimental and theoretical study of the coherent Rayleigh-Brillouin scattering in gases kinetic regime. Gas density perturbation waves were generated by two crossing pump laser beams through optical dipole forces. A probe beam was then coherently scattered from waves. The line shape light modeled using theory. model takes into account internal energy modes gas particles is applicable to both molecular atomic gases. discuss implication on theory photon matter interaction.
A detailed physical model for an asymmetric dielectric barrier discharge (DBD) in air driven by repetitive nanosecond voltage pulses is developed. In particular, modeling of DBD with high negative and positive combined dc bias carried out. Operation at compared operation low voltage, highlighting the advantage voltages, however effect backward-directed breakdown case results a decrease integral momentum transferred to gas. The use demonstrated be promising performance improvement. effects...
We suggest an approach for using microwave radiation in collisional, weakly ionized plasma diagnostics when dimensions are relatively small compared with the wavelength. show that this case can be based on measurement of scattered by oscillating dipole, similar to Rayleigh scattering atom light. Examples considered possibilities obtaining decaying parameters (time dependence charge density and information about loss rates, instance) from measured signal.
Direct measurements of the dielectric surface potential and its dynamics in asymmetric barrier discharge (DBD) plasma actuators show that charge builds up at extends far downstream plasma. The persists for a long time (tens minutes) after driving voltage has been turned off. For sinusoidal waveform, charges positively. With waveform consisting nanosecond pulses superimposed on dc bias, sign is same as (polarity) bias voltage. charging significantly affects DBD actuator performance.
Temporally resolved evolution of parameters in atmospheric plasma jet is studied by means microwave scattering, fast photographing, and measuring currents. It observed that streamer (“plasma bullet”) propagating along with gas flow generated immediately after the breakdown. demonstrated an afterglow column remains on way passing. Lifetime 3–5 μs, which longer than streamer.
We present a comprehensive model of plasma dynamics that enables detailed understanding the ways air induced in atmosphere wake laser-induced filament can be controlled by an additional laser pulse. Our self-consistently integrates plasma-kinetic, Navier−Stokes, electron heat conduction, and electron−vibration energy transfer equations, serving to reveal laser−plasma interaction regimes where lifetime substantially increased through efficient control over temperature, as well suppression...
A new method for temporally resolved measurements of absolute values plasma density applicable wide spectrum small-size atmospheric plasmas and utilizing Rayleigh microwave scattering on the tested object is proposed. The electron in an jet revealed presence two consecutive breakdowns during half-wave discharge-driven high voltage. ionization mechanisms both are considered.
In this paper we report the results on study of non-equilibrium nanosecond discharge generation in liquid media. Here studied both water and silicon transformer oil, present our findings behaviour depending global (applied) electric, emission spectrum shadow imaging discharge. We also discuss possible scenarios development suggest that operates a leader-type regime supported by electrostriction effect—creation nano-sized pores due to high local electric field.
This work presents a simple method for the characterization of streamers developing in cold atmospheric plasma jets. The is based upon stopping ('scattering') by means an external dc potential order to determine streamer head. experimental evidence presented this does not support model electrically insulated In fact, it shows that electrode transferred head along column which attached with no significant voltage drop. Based on proposed method, we various parameters such as charge ((1–2) ×...
It has been suggested that optical flashes observed in the upper atmosphere above giant thunderstorms (red sprites) are due to streamers. Such streamers initiated lower ionosphere by electron patches caused electromagnetic radiation from horizontal intracloud lightning and then develop downward static electric field thundercloud. The triggering conditions of streamer development analysed paper. Using similarity relations, known characteristics tips obtained earlier laboratory extended a...
A novel concept is analyzed of hypersonic cold-air magnetohydrodynamic (MHD) power generators and accelerators with ionization by electron beams. Ionization processes are considered in detail. Strong coupling between boundary layers electrode sheaths demonstrated, anode voltage fall MHD channels shown to be very high. potential sheath instability ways suppress it discussed. Electron beams capable generating an adequate conductivity cold air, while allowing full control stable operation...
Multiphoton ionization and electron recombination processes are studied in argon using coherent microwave Rayleigh scattering from a localized, resonance-enhanced multiphoton produced plasma. A time dependent one-dimensional plasma dynamic model is developed to predict the evolution of Experimental results spectrum rates good agreement with predictions.
Ignition in methane/air mixtures has been achieved using low energy seed laser pulses and an overlapping subcritical microwave pulse. It is shown that the extremely weak ionization of localizes deposition—leading to rapid heating, high temperatures, ignition. Multiple simultaneous localized regions ignition are also same Interactions pulse heating were observed schlieren shadowgraph record intensity scale interaction, for confirmation In addition, a coupled one-dimensional gasdynamic-plasma...