Download or read book Laser Induced Fluorescence Measurements Within a Laboratory Hall Thruster Postprint written by and published by . This book was released on 1999 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, we describe the results of a study of laser induced fluorescence velocimetry of ionic xenon in the plume and interior acceleration channel of a laboratory Hall type thruster operating at powers ranging from 250 to 725 W. Optical access to the interior of the Hall thruster is provided by a 1 mm axial slot in the insulator outer wall. Axial ion velocity profiles for four discharge voltages (100 V, 160 V, 200 V, 250 V) are measured as are radial velocity profiles in the near field plume. Internal neutral xenon axial velocity profiles are also measured at these conditions. For each test condition, the implied axial electric field is calculated from the measured ionic velocity profiles. These results are compared to previous plasma potential measurements performed with an emissive probe. The correspondence between the two sets of measurements indicates that the ionization and acceleration regions within the thruster are separated to some degree.

Download or read book Laser Induced Fluorescence Measurements on a Laboratory Hall Thruster Postprint written by and published by . This book was released on 1998 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, we describe the results of a study of laser induced fluorescence velocimetry of neutral xenon in the plume of a Hall type thruster operating at powers ranging from 250 to 725 W. Neutral velocities are seen to increase with thruster discharge voltage. There is no evidence for neutrals being accelerated in the near field plume. Velocities appear to remain constant past the cathode plane. In preparation for future ion velocimetry studies, the plume plasma potential profile is measured for a number of conditions. For a low power condition, the plasma potential profile is mapped through the ionization region into the interior of the thruster. For this condition, the electric field profile is calculated. We also find evidence of neutral xenon streaming toward the Hall thruster. These backstreaming neutrals make determination of neutral xenon velocities difficult. We believe the neutrals originate from the thruster plume wall impingement approximately 2 m from the thruster.

Download or read book Interior and Exterior Laser Induced Fluorescence and Plasma Potential Measurements on a Laboratory Hall Thruster Postprint written by and published by . This book was released on 1999 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, we describe the results of a study of laser induced fluorescence velocimetry of ionic xenon in the plume and interior acceleration channel of a laboratory Hall type thruster operating at powers ranging from 250 to 725 W. Optical access to the interior of the Hall thruster is provided by a 1 mm axial slot in the insulator outer wall. Axial ion velocity profiles for four discharge voltages (100 V, 160 V, 200 V, 250 V) are measured as are radial velocity profiles in the near field plume. Internal neutral xenon axial velocity profiles are also measured at these conditions. For comparison, the plume plasma potential profile is measured with an emissive probe. These probe based potential measurements extend from 50 mm outside the plume to the near anode region for all but the highest discharge voltage condition. For each condition, the axial electric field is calculated from the plasma potential. In addition, an estimate of the local electron temperature is calculated from the Bohm criterion at the location of each plasma potential measurement.

Download or read book Interior and Exterior Laser Induced Fluorescence and Plasma Measurements Within a Hall Thruster Postprint written by and published by . This book was released on 2002 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe results of a study of emissive-probe-based plasma potential measurements and laser-induced fluorescence velocimetry of neutral and singly ionized xenon in the plume and interior portions of the acceleration channel of a Hall thruster plasma discharge operating at powers ranging from 250 to 725 W. Axial ion and neutral velocity profiles for four discharge voltage conditions (100, 160, 200, and 250V) are measured as are radial ion velocity profiles in the near-field plume. Axial ion velocity measurements both inside and outside the thruster as well as radial velocity measurements outside the thruster are performed using laser-induced fluorescence with nonresonant signal detection. Neutral axial velocity measurements are similarly performed in the interior of the Hall thruster with resonance fluorescence collection. Optical access to the interior of the Hall thruster is provided by a 1-mm-wide axial slot in the outer insulator wall. The majority of the ion velocity measurements used partially saturated fluorescence to improve the signal-to-noise ratio. Probe-based plasma potential measurements extend from 50 mm outside the thruster exit plane to the near anode region for all but the highest discharge voltage condition. For each condition, the axial electric field is calculated from the plasma potential, and the local electron temperature is determined from the difference between the floating and plasma potentials. These two sets of measurements delineate the structure of the plasma and indicate that the ionization and acceleration regions are somewhat separated. Also, these measurements indicate a region of low electric field near the thruster exit, especially at the higher discharge voltages. This region of near constant potential (low electric field) may be a result of oscillations, which enhance the local plasma conductivity.

Download or read book Laser induced Fluorescence Measurement of Ion Velocities in the Plume of a Hall Effect Thruster written by George J. Williams and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ion Velocity Measurements in a Linear Hall Thruster written by and published by . This book was released on 2005 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents the general operation and the near exit plane velocity field of the Stanford Linear Hall thruster in a high vacuum environment. The ionized propellant velocities were measured using laser induced fluorescence of the excited state xenon ionic transition at 834.7 nm. Ion velocities were interrogated from the channel exit plane to a distance 30 mm from it. Both axial and transverse (along the electron Hall current direction) velocities were measured. These results presented here, combined with those of previous works, highlight the high sensitivity of electron mobility inside and outside the channel, depending on the background gas density, type of wall material, or magnetic field intensity. When operated with a low background pressure, the particular Hall discharge studied here creates an ion accelerating electrostatic field mainly outside of the channel, in a narrow zone located 5-20 mm away from the exit plane.

Download or read book Laser induced Fluorescence Measurements Within an Arcjet Thruster Nozzle written by P. Victor Storm and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser induced Fluorescence Measurements of a Two stage Electrothermal Thruster Plume written by Vincent P. Chiravalle and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of the Feasibility of Using Laser Induced Fluorescence for Concentration Measurements by Diatomic Sulfur written by William D. Harris (Jr.) and published by . This book was released on 1982 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feasibility of using laser induced fluorescence to measure total S2 number densities in a laboratory environment is studied. A rate equation analysis modeling transitions within the B to the 3rd power negative summation u-to the 3rd power negative summation g system of S2 is developed and applied to model the frequency prime = 9, frequency double prime = 6 transition at 3214.6 angstroms. Excitation spectra were obtained over the range of 2890 to 2810 angstroms clearly showing the frequency double prime = 0, frequency prime = 8 and frequency double prime = 0, frequency prime = 9 absorption bands. Fluorescence scans of the frequency prime = 8, frequency double prime = 1 through 24 and frequency prime = 9, frequency double prime = 1 through 25 were taken. After these broad spectra were identified, further investigations of the frequency prime = 9, frequency double prime = 6 transition included fluorescence intensity versus temperature, laser power, and pressure. Additional measurements of quenching, radiative lifetime and self absorption are made.

Download or read book Laser induced Fluorescence Diagnostics for Xenon Hall Thrusters written by R. J. Cedolin and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Use of Fiber Optics and Laser induced Fluorescence for Remote Measurements of UF6 in Strong Rotation written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) and other laser-based techniques are being employed in an increasing number of gas and flow field diagnostic applications. In some instances, the necessary instrumentation requires unavailable space and is not portable. Sometimes the process region of interest is relatively inaccessible. These factors complicate and hinder deployment of laser diagnostic techniques. A fiber optics based method for delivering the laser and for returning optical signals can be used to circumvent these problems. Reported here is a demonstration of a fiber optics system for remote monitoring of UF6 density and temperature by the LIF method. The description consists of a discussion of a fiber system that conveys the laser beam to the points of interest and a fiber system which transmits the LIF signal to a photomultiplier tube. Representative results from a static gas cell and a centrifuge are presented.

Download or read book Measurement of Gas Density and Temperature Distributions in Strongly Rotating UF6 Using Laser induced Fluorescence written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A new technique for using Laser Induced Fluorescence (LIF) signals to measure the distribution of gas density and temperature in strongly rotating UF6 gas is presented. An external pulsed laser is used to excite the rotating UF6 gas, producing an exponentially decaying fluorescence signal. A multi-channel fiber optics system simultaneously collects the fluorescence signals emanating from a number of points in the gas. The signals from each optical channel are digitized and processed to determine the fluorescence signal intensity and decay lifetime at each of the points of observation by means of a least squares fitting process. Gas densities and temperatures are then determined from the intensity and lifetime data. A recently constructed LIF probe system is described and an analysis of the unfolding techniques necessary to process the signal data is presented. Preliminary data, obtained in tests of the probe system in a laboratory rotor, are presented.

Download or read book Use of Fiber Optics and Laser induced Fluorescence for Remote Measurements of UF6 in Strong Rotation written by Stephen William Allison and published by . This book was released on 1983 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced fluorescence (LIF) and other laser-based techniques are being employed in an increasing number of gas and flow field diagnostic applications. In some instances, the necessary instrumentation requires unavailable space and is not portable. Sometimes the process region of interest is relatively inaccessible. These factors complicate and hinder deployment of laser diagnostic techniques. A fiber optics based method for delivering the laser and for returning optical signals can be used to circumvent these problems. Reported here is a demonstration of a fiber optics system for remote monitoring of UF6 density and temperature by the LIF method. The description consists of a discussion of a fiber system that conveys the laser beam to the points of interest and a fiber system which transmits the LIF signal to a photomultiplier tube. Representative results from a static gas cell and a centrifuge are presented.

Download or read book Laser Induced Fluorescence Measurements of Thermal and Statistical Properties of a Gas Using Optically Pumped Sodium Vapor written by Christopher Calvin Dobson and published by . This book was released on 1998 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laser induced Fluorescence Measurements of Dual Plumes and Comparison of Laser induced Fluorescence and Conductivity Probe Measurements written by Joseph Coleman Chrzan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The laser-induced fluorescence (LIF) technique is used to visualize and quantify the concentration field around a conductivity probe. The LIF data are compared to the signal collected by the conductivity probe. The objective is to compare the signal of the contact-sensor to the "ground-truth" measurement of the LIF data. Detailed comparison of the temporal response and the peak detection are presented. In addition, a proof-of-concept of a two-color LIF technique is presented using Rhodamine 6G paired with an Argon-ion laser and simultaneously Oxazine 725 paired with a Krypton-ion laser. Optical filters on two digital cameras isolate the emitted light from these respective laser/dye combinations. The objective is to provide detailed quantitation of two over-lapping (non-reactive)chemical plumes.

Download or read book Excitation detection strategies for OH planar laser induced fluorescence measurements in the presence of interfering fuel signal and absorption effects written by and published by . This book was released on 2011 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Planar Laser induced Fluorescence Measurements of the Hydroxyl Radical Concentration in an Acoustically Excited Dump Combustor written by Christopher P. Cadou and published by . This book was released on 1991 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: