Download or read book ExB Measurements of a 200 W Xenon Hall Thruster Preprint written by and published by . This book was released on 2007 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Angularly resolved ion species fractions of Xe+1, Xe+2, and Xe+3 in a low power xenon Hall thruster Busek BHT-200 plume were measured using an ExB probe under a variety of thruster operating conditions and background pressures. The thruster was operated at several operating conditions by varying the anode potential of the thruster from 200 V to 325 V in 25 V increments. Measurements of the ion species fractions were made 90 from thruster centerline 60 cm downstream of the exit plane. At reduced discharge voltages, the species fractions of multiply-charged xenon ions were lower, while at increased discharge voltages, Xe+2 and Xe+3 showed an increase in their respective ion species fractions. At angles greater than 35, a low energy peak was observed suggesting additional collisions in the far-field produce a low energy ion population. Finally, measurements were directed toward characterizing chamber backpressure effects on the plume species fractions at oblique angles between 35-90 . In the presence of additional background neutrals, production of mutiply-charged ions increased throughout the plume as a result of increased collisions and scattering.
Download or read book ExB Measurements of a 200 W Xenon Hall Thruster written by and published by . This book was released on 2005 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Angularly resolved ion species fractions of Xe+1, Xe+2, and Xe+3 in the Busek BHT-200-X3 xenon Hall thruster plume were measured using an ExB probe for several operating conditions. The thruster was operated at nominal anode potential of 250 V and swept from 200 V to 325 V in 25 V increments. The ExB probe was placed 60 cm downstream of the exit plane and rotated up to 90 degrees from centerline. At the nominal anode potential, the ion species fractions of the multiply charged xenon ions were lower, while at increased discharged voltages Xe+2 and Xe+3 showed an increase in their respective species fractions. At angles beyond 35 degrees, an additional low energy peak was observed suggesting additional collisions in the far-field produce these low energy ions. Our goals are to characterize the thruster ion distribution and to verify predictions of various numerical models by investigating the effects of thruster operation and chamber backpressure on the production of charge exchange ions.
Download or read book Test Results of a 200 W Class Hall Thruster written by and published by . This book was released on 1999 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Complementary Density Measurements for the 200W Busek Hall Thruster PREPRINT written by and published by . This book was released on 2006 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of two complementary methods of measuring the near field plasma densities of a 200W Busek X3 Hall thruster are presented. Both a Faraday probe and microwave interferometry system are used to examine the density distribution of the thruster plasma at regular spatial intervals. Both experiments are performed in situ under the same conditions. The resulting density distributions obtained from both experiments are presented. Advantages and uncertainties of both methods are presented, as well as how comparison between the two data sets can account for the uncertainties of each method alone.
Download or read book Evolution of the Ion Velocity Distribution in the Near Field of a 200 W Hall Thruster Preprint written by and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents an analysis of near plume velocity distributions of the Busek BHT-200-X3 200 W laboratory Hall thruster derived from laser-induced fluorescence measurements of the 5d[4]7/2-6p[3]5/2 xenon ion excited state transition. The evolution of the axial and radial velocity distributions is presented from the exit plane to approximately 0.7 exit diameters downstream. It is shown that the distributions evolve significantly between the exit channel center and the inner portion of the channel where there are high frac-tions of low velocity ions. It is believed that this may be due to the slight inward focus of the xenon ion propellant colliding on the surface, recombining, and subsequently being re-ionized. Low axial velocity ions appear downstream of the thruster exit plane. While their origin is not entirely certain, the most likely explanation appears to be cross annular flow. Strong evidence of charge exchange is also evident producing high velocity wings on the primary ion velocity peak reminiscent of ion energy analyzer studies of other thrusters. A survey of the axial and radial velocity distributions along the exposed exterior boron nitride nose cone covering the central magnetic pole is performed to determine the behavior of the ions impacting this critical surface. The VDF is ideal for comparison with numerical simulations since it allows for direct comparison of the fundamental ion acceleration. External VDF data can even provide limited insight as to the internal ion formation and acceleration processes.
Download or read book Comparison of Numerical and Experimental Near Field Plasma Properties of the BHT 200 X3 Hall Thruster Preprint written by and published by . This book was released on 2006 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-field ion velocity distributions of a BusekBHT-200-X3 xenon Hall thruster obtained through numerical simulation are compared with laser-induced fluorescence measurements taken for one nominal operating condition. The numerical code Hybrid-PIC Hall, a 2D hybrid particle-in-cell model, is used to simulate an axisymmetric cross section of the plasma acceleration zone. A set of nine HP Hall simulations are run using three different cathode positions and Bohm electron mobility coefficients to study the effects of these parameters on ion acceleration. Six additional cases were run in an attempt to better match the simulation results to the experimental data. For model validation, agreement between the numerical and experimental results is examined. The results show that it is difficult to match both the global operational parameters (i.e, thrust, discharge current, and beam current) and the ion velocity distributions. The shape of the axial velocity distributions can be closely matched by using high Bohm electron mobility values. However, this correlation comes at the expense of peak ion velocity and discharge current agreement. Radial velocity distributions are more closely matched by the simulations, but the simulations uniformly predict lower than measured inward and higher than measured outward radial velocity components (relative to the centerline) from the annular acceleration channel.
Download or read book Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout most of the twentieth century, electric propulsion was considered the technology of the future. Now, the future has arrived. This important new book explains the fundamentals of electric propulsion for spacecraft and describes in detail the physics and characteristics of the two major electric thrusters in use today, ion and Hall thrusters. The authors provide an introduction to plasma physics in order to allow readers to understand the models and derivations used in determining electric thruster performance. They then go on to present detailed explanations of: Thruster principles Ion thruster plasma generators and accelerator grids Hollow cathodes Hall thrusters Ion and Hall thruster plumes Flight ion and Hall thrusters Based largely on research and development performed at the Jet Propulsion Laboratory (JPL) and complemented with scores of tables, figures, homework problems, and references, Fundamentals of Electric Propulsion: Ion and Hall Thrusters is an indispensable textbook for advanced undergraduate and graduate students who are preparing to enter the aerospace industry. It also serves as an equally valuable resource for professional engineers already at work in the field.
Download or read book Performance Evaluation of the SPT 140 written by and published by . This book was released on 1997 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cathodic Arcs written by André Anders and published by Springer Science & Business Media. This book was released on 2009-07-30 with total page 555 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cathodic arcs are among the longest studied yet least understood objects in science. Plasma-generating, tiny spots appear on the cathode; they are highly dynamic and hard to control. With an approach emphasizing the fractal character of cathode spots, strongly fluctuating plasma properties are described such as the presence of multiply charged ions that move with supersonic velocity. Richly illustrated, the book also deals with practical issues, such as arc source construction, macroparticle removal, and the synthesis of dense, well adherent coatings. The book spans a bridge from plasma physics to coatings technology based on energetic condensation, appealing to scientists, practitioners and graduate students alike.
Download or read book Laser Spectroscopy written by Wolfgang Demtröder and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of lasers on spectroscopy can hardly be overestimated. Lasers re present intense light sources with spectral energy densities which may exceed those of i ncoheren t sources by severa 1 orders of magnitude. Furthermore be cause of their extremely small bandwidth, single-mode lasers allow a spectral resolution which far exceeds that of conventional spectrometers. Many experi ments which could not be done before the application of lasers because of lack of intensity or insufficient resol ution are readily performed wi th lasers. Now several thousands of laser lines are known which span the whole spec tral range from the vacuum-ultraviolet to the far-infrared region. Of parti cular interest are the continuously tunable lasers which may in many cases replace wavelength-selecting elements, such as spectrometers or interferome ters. In combination with optical frequency mixing, techniques such conti nuously tunable monochromatic coherent light sources are available at nearly any desired wavelength above 100 nm.
Download or read book Nondestructive Materials Characterization written by Norbert G. H. Meyendorf and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an emphasis on aircraft materials, this book describes techniques for the material characterization to detect and quantify degradation processes such as corrosion and fatigue. It introduces readers to these techniques based on x-ray, ultrasonic, optical and thermal principles and demonstrates the potential of the techniques for a wide variety of applications concerning aircraft materials, especially aluminum and titanium alloys. The advantages and disadvantages of various techniques are evaluated.
Download or read book Air and Spaceborne Radar Systems written by Philippe Lacomme and published by William Andrew. This book was released on 2001 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Intended for actual users of radar, the book focuses on the history, main principles, functions, modes, properties and specific nature of modern airborne radar. It examines radar's role within the system when carrying out its assigned missions, showing the possibilities of radar, it's limitations and a discussion of how radar may evolve in the future.
Download or read book S ntesi mem ria 2000 2001 written by Institut d'Estudis Catalans and published by Institut d'Estudis Catalans. This book was released on 2001-01-01 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Astrophysical and Laboratory Plasmas written by A.J. Willis and published by Springer Science & Business Media. This book was released on 1996-08-31 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout his career Sir Robert Wilson has demonstrated that advances in a wide variety of fields in astrophysics and laboratory physics are achievable through the application of fundamental plasma spectroscopy. His work has included: optical studies that probed the nature of interstellar dust and first revealed the existence of O star winds; vacuum ultraviolet and X-ray diagnosis of fusion plasmas; rocket ultraviolet and X-ray observations of the Sun; and the conception, development and use of the International Ultraviolet Explorer (IUE) satellite which has contributed greatly to stellar, interstellar and extragalactic astrophysics. This volume contains reviews honouring Sir Robert and reflecting his interests.
Download or read book Automotive Radar Sensors in Silicon Technologies written by Vipul Jain and published by Springer Science & Business Media. This book was released on 2012-09-27 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the leading causes of automobile accidents is the slow reaction of the driver while responding to a hazardous situation. State-of-the-art wireless electronics can automate several driving functions, leading to significant reduction in human error and improvement in vehicle safety. With continuous transistor scaling, silicon fabrication technology now has the potential to substantially reduce the cost of automotive radar sensors. This book bridges an existing gap between information available on dependable system/architecture design and circuit design. It provides the background of the field and detailed description of recent research and development of silicon-based radar sensors. System-level requirements and circuit topologies for radar transceivers are described in detail. Holistic approaches towards designing radar sensors are validated with several examples of highly-integrated radar ICs in silicon technologies. Circuit techniques to design millimeter-wave circuits in silicon technologies are discussed in depth.
Download or read book Radiowave Propagation in Satellite Communications written by Louis J. Ippolito and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiowave Propagation in Communications was written with two basic objec tives: (l) to present an up-to-date review of the major radiowave propagation phenomena which hinder reliable space communications, and (2) to describe how these propagation phenomena affect the design and performance of satellite communications systems. Earth-orbiting satellites are employed extensively for the relay of information in a vast array of telecommunications, meteorological, government, and sci entific applications. Satellite systems rely on the transmission of radiowaves to and from the satellite and are dependent on the propagation characteristics of the transmission path, primarily the earth's atmosphere. Radiowave propagation thus plays a very important part in the design and ultimate performance of space communications systems. This book presents, for the first time, the meshing in a single publication of the fundamentals of radiowave propagation factors with a discussion of the practical consequences of these factors on satellite communications systems. Two major subfie1ds are involved in this book. Radiowave propagation, which is basically applied electromagnetic theory, provides the theory and an alytical tools for the first several chapters. Later chapters then apply propagation effects to the field of electrical engineering involved with satellite communi cations. The material progresses from the essential aspects of radiowave prop agation to the application of practical methods and techniques in the design and performance of satellite communications systems.
Download or read book Physics of Ionized Gases written by Damir Veža and published by Nova Biomedical Books. This book was released on 1995 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics of Ionized Gases
