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- Glow discharges (2)
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Articles 1 - 8 of 8
Full-Text Articles in Plasma and Beam Physics
A Numerical Simulation Of A Carbon Black Suspension Cell Via A Time-Reversed, Double Layer Compute Algorithm, Gregg T. Anderson
A Numerical Simulation Of A Carbon Black Suspension Cell Via A Time-Reversed, Double Layer Compute Algorithm, Gregg T. Anderson
Theses and Dissertations
A numerical simulation of a carbon black suspension cell is explored which models a laser-induced plasma within a liquid ethanol medium of approximately 1 mm thickness. The simulation model assumes a laser pulse with a pulse width of approximately 9 nsecs propagating in the left-to-right direction striking the front surface of the medium and focusing to a spot within the liquid volume. When the energy density within a given irradiated volume is sufficiently high, it ignites the carbon particles and generates a large number of free electrons, i.e., a plasma. The plasma couples with the in-coming laser energy on a …
Resonant Enhancement Of Relativistic Electron Fluxes During Geomagnetically Active Periods, I Roth, M Temerin, M K. Hudson
Resonant Enhancement Of Relativistic Electron Fluxes During Geomagnetically Active Periods, I Roth, M Temerin, M K. Hudson
Dartmouth Scholarship
The strong increase in the ̄ux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced signi®cantly due to injection of 10±100 keV electrons during the substorm. Electrons which drift in the gradient and curvature of the magnetic ®eld generate the rising tones of VLF whistler chorus. The seed population of relativ- istic electrons which bounce along the inhomogeneous magnetic ®eld, interacts resonantly with the whistler waves. Whistler wave …
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Temperature Dependence Of Stark Width Of The 463.054 Nm Nii Spectral Line, Vladimir Milosavljevic, Ruzica Konjevic, Stevan Djenize
Articles
Stark width of the 463.054 nm singly ionized nitrogen spectral line, that belong to transition, have been measured in a linear pulsed, low pressure, arc discharge. The working gas was helium-nitrogen-oxygen mixture. Electron densities of 0.751023 to 1.451023 were determined in the electron temperature range between 30000 K - 38000 K. The measured values have been compared with our calculated data, using the modified semiempirical approximation. On the basis of the agreement among experimental and theoretical Stark width data, the isolated 463.054 nm NII spectral line can be recommended as convenient spectral line for plasma diagnostics.
A Continuous Wave Atomic Bromine Laser Produced By Photolysis Of Iodine Monobromide, Brian A. Smith
A Continuous Wave Atomic Bromine Laser Produced By Photolysis Of Iodine Monobromide, Brian A. Smith
Theses and Dissertations
An apparatus to generate continuous wave (CW) lasing at 2.714 µm by Br(2P1/2) atoms produced from photodissociation of IBr was designed, constructed and tested. A frequency doubled Nd:YAG laser firing 8 ns, 850 mJ pulses at 532 nm was used to photodissociate static IBr vapor inside a flow nozzle. The CaF2 windows on either side of the nozzle proved to have a damage threshold below the threshold for lasing. Pulsed lasing in static mode was not observed. Therefore, CW lasing in flow mode, using an Ar+ laser at 488 nm, could not be investigated.
Numerical Solutions To The Two Dimensional Boltzmann Equation, Christopher G. Smithtro
Numerical Solutions To The Two Dimensional Boltzmann Equation, Christopher G. Smithtro
Theses and Dissertations
A strict kinetic, two-dimensional model of the electron kinetics within a glow discharge positive column is developed. The problem is solved in cylindrical geometry using the standard two-term Legendre expansion of the electron velocity distribution function. The model establishes a steady state solution, such that the net ionization rate is exactly balanced by the wall loss. In addition to a thorough analytic development, we present the numerical techniques used to solve the resulting elliptic partial differential equation, including an efficient method to treat sparse banded matrices. The model is validated against published results, local and nonlocal kinetic approximations, and a …
Laser Beam Combining And Cleanup Via Stimulated Brillouin Scattering In Multi-Mode Optical Fibers, Blake C. Rodgers
Laser Beam Combining And Cleanup Via Stimulated Brillouin Scattering In Multi-Mode Optical Fibers, Blake C. Rodgers
Theses and Dissertations
The main objective of this thesis was to demonstrate the feasibility of combining and cleaning up multiple laser beams via Stimulated Brillouin Scattering (SBS) in a multi-mode optical fiber. Beam combining via SBS in an optical fiber is of interest because of the low SBS threshold power in an optical fiber allowing low power diode laser beams to be combined into one high power beam. SBS theory and some of the important historical results are described briefly. The experimental results clearly indicate that SBS in multi-mode optical fiber can indeed combine laser beams and clean up the beams at the …
Double Layer Effects On Shock Wave Propagation, Shannon L. Walker
Double Layer Effects On Shock Wave Propagation, Shannon L. Walker
Theses and Dissertations
An analysis and assessment of two mechanisms in plasma shock interactions was conducted under conditions typically encountered in a weakly ionized glow discharge. The mechanisms of a spatially-dependent electron temperature and additional electron impact ionization at the shock front were examined for effects on shock structure and propagation. These mechanisms were incorporated into an existing one-dimensional, time-dependent, fluid dynamics code that uses the Riemami problem as a basis and numerically solves the Euler equations for two fluids: the neutral gas and the charged component. The spatial variation in electron temperature was modeled as a shock-centered rise in temperature. Additional ionization …
Direct Current Glow Discharges In Atmospheric Air, Robert H. Stark, Karl H. Schoenbach
Direct Current Glow Discharges In Atmospheric Air, Robert H. Stark, Karl H. Schoenbach
Bioelectrics Publications
Direct current glow discharges have been operated in atmospheric air by using 100 μm microhollow cathode discharges as plasma cathodes. The glow discharges were operated at currents of up to 22 mA, corresponding to current densities of 3.8 A/cm2 and at average electric fields of 1.2 kV/cm. Electron densities in the glow are in the range from 1012 to 1013 cm−3. Varying the current of the microhollow cathode discharge allows us to control the current in the atmospheric pressure glow discharge. Large volume atmospheric pressure air plasmas can be generated by operating microhollow cathode discharges …