Download or read book Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe. The temporal profiles of the plasma density can be obtained from the voltage traces of the discharge of the charged probe capacitance by the ion current from the expanding plasma. The temporal profiles of the plasma density, at two different distances from the surface of the ferroelectric plasma source, could be further fitted by using the density profiles for the expanding plasma. This gives the initial values of the plasma density and electron temperature at the surface. The method could be useful for any pulsed discharge, which is accompanied by considerable electromagnetic noise, if the initial plasma parameters might be deduced from measurements in expanding plasma.
Download or read book Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma written by A. Dunaevsky and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Operation of Ferroelectric Plasma Sources in a Gas Discharge Mode written by A. Dunaevsky and published by . This book was released on 2004 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Plasma Density in a Gas filled Ionizing Laser Focus written by Nathan Edward Heilmann and published by . This book was released on 2012 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: We use an interferometric method for measuring the plasma density in a laser-induced plasma as a function of time. Any changes in the density within 5 ns of generation is due plasma expansion and not recombination. The analytic solution for plasma expansion derived for ultracold Neutral Plasmas describes the expansion of our laser produced Neon plasma of densities up to approximately 40 Torr. A model for the utlracold neutral plasmas, in comparison with measurements of our plasmas, can be used to extract an electron temperature. Currently our plasmas have shown to have an electron temperature of approximately 44 eV.
Download or read book Operation of Ferroelectric Plasma Sources in a Gas Discharge Mode written by A. Dunaevsky and published by . This book was released on 2004 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Measurements of Plasma Density and Temperature in a Plasma Opening Switch written by Lynne Kay Adler and published by . This book was released on 1993 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectroscopic Study of the Plasma Produced by a Ferroelectric Plasma Source written by Or Peleg and published by . This book was released on 2004 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volumetric Plasma Source Development and Characterization written by and published by . This book was released on 2008 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of plasma sources with densities and temperatures in the 1015-1017 cm−3 and 1-10eV ranges which are slowly varying over several hundreds of nanoseconds within several cubic centimeter volumes is of interest for applications such as intense electron beam focusing as part of the x-ray radiography program. In particular, theoretical work [1,2] suggests that replacing neutral gas in electron beam focusing cells with highly conductive, pre-ionized plasma increases the time-averaged e-beam intensity on target, resulting in brighter x-ray sources. This LDRD project was an attempt to generate such a plasma source from fine metal wires. A high voltage (20-60kV), high current (12-45kA) capacitive discharge was sent through a 100 [mu]m diameter aluminum wire forming a plasma. The plasma's expansion was measured in time and space using spectroscopic techniques. Lineshapes and intensities from various plasma species were used to determine electron and ion densities and temperatures. Electron densities from the mid-1015 to mid-1016 cm−3 were generated with corresponding electron temperatures of between 1 and 10eV. These parameters were measured at distances of up to 1.85 cm from the wire surface at times in excess of 1 [mu]s from the initial wire breakdown event. In addition, a hydrocarbon plasma from surface contaminants on the wire was also measured. Control of these contaminants by judicious choice of wire material, size, and/or surface coating allows for the ability to generate plasmas with similar density and temperature to those given above, but with lower atomic masses.
Download or read book Pressure Gradient Effects On Two Dimensional Plasma Expansion written by R. F. Smith and published by . This book was released on 2004 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in interferometry has allowed for the characterization of the electron density expansion within a laser produced plasma to within 10 {micro}m of the target surface and over picosecond timescales. This technique employs the high brightness output of the transient gain Ni-like Pd collisional x-ray laser at 14.7 nm to construct an effective moving picture of the two-dimensional (2-D) expansion of the plasma. We present experimentally measured density profiles of an expanding Al plasma generated through laser irradiation in a 14mm line focus geometry. Significant lateral expansion was observed at all times as well as a pronounced on-axis electron density dip. Detailed modeling with a 2-D plasma physics code gives good agreement to experimental observations. Large pressure gradients associated with the tight focal spot conditions are calculated to dominate in shaping the plasma density profile.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plasma Property Estimation from Dual wavelength Interferometry written by Andrew J. Hamilton and published by . This book was released on 2017 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diagnostics are necessary for measurement of plasma parameters such as electron, ion and atomic densities, electron temperature, plasma expansion velocity and spatial resolution of density gradients. These parameters play a critical role in defining how a plasma will interact with electromagnetic radiation. For example, the plasma black-out phenomenon occurs when electromagnetic waves are at frequencies below the plasma frequency, where plasma frequency is a function of electron density. Wave propagation diagnostics can improve understanding of a plasma when measurement supports parameter estimation. In this report, the dual-wavelength interferometry method provides a single diagnostic capability to measure plasma expansion velocity, atomic density and electron densities. Using a laboratory plasma created with wire-ablation pulsed-power techniques and the Sarkisov model, electron and atomic densities are estimated for copper and aluminum plasmas.
Download or read book Measurements of Plasma Expansion Due to Background Gas in the Electron Diffusion Gauge Experiment written by Kyle Adam Morrison and published by . This book was released on 2003 with total page 22707 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recombining Plasma Expanding in Low Pressure Region written by R. P. Dahiya and published by . This book was released on 2003 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: High density thermal plasma expanding in low-pressure region is of immense scientific interest and has numerous applications. The monomer seeded plasma is utilized for plasma processing of surfaces, i.e. deposition, surface etching, nitriding and for many more applications depending on the seeding materials. Conditions prevailing in the Tokomak edge plasma can also be simulated using the low temperature, high flux obtained with cascaded arc thermal plasma source. Various species of the high density flowing plasma generated in a narrow channel (few mm diameter) of an arc discharge are usually in thermal equilibrium. In this presentation experimental measurements made in the thermal plasma with particular reference to the kinetics in molecular plasma and surface nitriding will be discussed. The cascaded arc source is coupled to a low-pressure chamber wherein the plasma generated in the source expands while propagating in the axial direction. Typical parameters of argon plasma in the expansion region are: plasma density, 10(exp 19)/cu m, electron temperature, 3000 K for argon flow rate of 3 slpm and 60 A arc current The current in the arc is distributed over three water-cooled tungsten cathodes, which not only prolongs the life of electrodes but also improves the uniformity of the system. If argon is replaced with molecular gas hydrogen / nitrogen, recombination processes set in the expanding plasma. The plasma density drops significantly and the electron temperature also reduces. In hydrogen plasma, charge transfer between the rovibrationally excited hydrogen molecules followed by dissociative recombination reactions provides the fast loss mechanism. Axial magnetic field helps to contain and prolong the hydrogen plasma beam in the chamber. Side injection of hydrogen in one of the cascaded arc plates stabilizes the arc, improves the ion flux, and is also beneficial for improving the cathode life.
Download or read book Plasma Catalysis written by Annemie Bogaerts and published by MDPI. This book was released on 2019-04-02 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, methane conversion into higher hydrocarbons or oxygenates. It is also widely used for air pollution control (e.g., VOC remediation). Plasma catalysis allows thermodynamically difficult reactions to proceed at ambient pressure and temperature, due to activation of the gas molecules by energetic electrons created in the plasma. However, plasma is very reactive but not selective, and thus a catalyst is needed to improve the selectivity. In spite of the growing interest in plasma catalysis, the underlying mechanisms of the (possible) synergy between plasma and catalyst are not yet fully understood. Indeed, plasma catalysis is quite complicated, as the plasma will affect the catalyst and vice versa. Moreover, due to the reactive plasma environment, the most suitable catalysts will probably be different from thermal catalysts. More research is needed to better understand the plasma–catalyst interactions, in order to further improve the applications.
Download or read book Digest of Technical Papers written by Kenneth R. Prestwich and published by . This book was released on 1993 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1974 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1983 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
