Download or read book Low Power Magnetically Shielded Hall Thrusters written by Ryan Conversano and published by . This book was released on 2015 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents an investigation of the applicability of magnetic shielding to low-power Hall thrusters as a means to significantly improve operational lifetime. The key life-limiting factors of conventional Hall thrusters, including ion-bombardment sputter erosion of the discharge channel and high-energy electron power deposition to the channel walls, have been investigated extensively for a wide range of thruster scales. As thruster power is reduced to the "miniature" (i.e. sub-500 W) power regime, the increased surface-to-volume ratio of the discharge channel and decreased thruster component sizes promotes increased plasma-wall interactions and susceptibility to overheating, thereby reducing thruster operational lifetime and performance. Although methods for compensating for these issues have been investigated, unshielded miniature Hall thrusters are generally limited to sub-45% anode efficiencies and maximum lifetimes on the order of 1,000 h. A magnetically shielded magnetic field topology aims to maintain a low electron temperature along the channel surfaces and a plasma potential near that of the discharge voltage along the entire surface of the discharge channel along its axial length. These features result in a reduction of the kinetic energy of ions that impact the channel surfaces to near to or below the sputtering threshold, thus preventing significant ion-bombardment erosion of the discharge channel. Improved confinement of high-energy electrons is another byproduct of the field structure, aiding in the reduction of electron power deposition to the channel. Magnetic shielding has been shown to dramatically reduce plasma-wall interactions on 4 - 6 kW Hall thrusters, resulting in significant increases in projected operational lifetimes with minimal effects to thruster performance. In an effort to explore the scalability of magnetic shielding to low-power devices, two magnetically shielded miniature Hall thrusters were designed, fabricated and tested. The performance of the first thruster, called the MaSMi 40, was characterized at an operating condition of 275 V and 325 W. A peak thrust of approximately 13 mN with a specific impulse of approximately 1,100 s at an anode efficiency of approximately 22% were measured at the nominal operating point. Observations of the near exit plasma discharge during operation, and the discharge channel after operation, suggested that the outer channel wall of the thruster was well shielded from ion bombardment while the inner channel wall appeared to be weakly shielded. Further analysis concluded that the MaSMi-40 generated a partially-magnetically shielded field topology. However, the shortcomings of the MaSMi-40's magnetic circuit design were investigated in detail and are now well understood. The second design iteration in the development of a low-power magnetically shielded Hall thruster was the MaSMi-60. Magnetic field measurements confirmed that a symmetric and fully shielded magnetic field topology was generated by this device across a wide range of possible operating conditions. At operating powers of 160 W to nearly 750 W, the key performance metrics of the MaSMi-60 included a measured thrust ranging from approximately 8 mN to over 33 mN with anode specific impulses of up to approximately 1370 s at anode efficiencies of over 28%. Downstream plume measurements identified the primary factors contributing to the low anode efficiency. Visual observations of the discharge plasma and channel walls during and after thruster operation offered strong evidence of magnetic shielding. Erosion rates of the channel were approximated using carbon backsputter measurements; the results suggested a 10x - 100x decrease in wall erosion compared to unshielded Hall thrusters, corresponding to an equal increase in discharge channel lifetime compared to conventional miniature unshielded Hall thrusters. The physics and behaviors of the MaSMi-60's plasma discharge upstream of and in the near-field of the thruster exit plane were investigated using Hall2De, the 2-D axisymmetric code developed at the Jet Propulsion Laboratory for the simulation of the partially ionized plasma in Hall thrusters. Simulations of the MaSMi-60 suggested that the thruster achieved the plasma properties required for effective magnetic shielding, including low electron temperatures and a near-constant plasma potential along the channel walls. This was the final piece of evidence suggesting that magnetic shielding was attained at the miniature scale. The experimentally measured performance of the MaSMi-60 was captured by the Hall2De model, offering physical explanations for the low measured anode efficiency and leading to suggestions for improving the performance in future design iterations.
Download or read book Magnetic Shielding Topology Applied to Low Power Hall Thrusters written by Lou Grimaud and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hall thrusters are one of the most used rocket electric propulsion technology. They combine moderate specific impulse with high thrust to power ratio which makes them ideal for a wide range of practical commercial and scientific applications. One of their limitations is the erosion of the thruster walls which reduces their lifespan.The magnetic shielding topology is a proposed solution to prolong the lifespan. It is implemented on a small200W Hall thruster.In this thesis the scaling of classical unshielded Hall thrusters down to 200 and 100W is discussed. A 200W low power magnetically shielded Hall thruster is compared with an identically sized unshielded one. The ion behavior inside the thruster is measured and significant differences are found across the discharge channel.Both thrusters are tested with classical BN-SiO2 and graphite walls. The magnetically shielded thruster is not sensitive to the material change while the discharge current increase by 25% in the unshielded one. The result is a maximum efficiency of 38% for boron nitride in the unshielded thruster but only 31% with graphite.The shielded thruster achieves a significantly lower efficiency with only 25% efficiency with both materials.Analysis of the experimental results as well as simulations of the thrusters reveal that the performance difference is mostly caused by low propellant utilization. This low propellant utilization comes from the fact that the ionization region doesn't cover all of the discharge channel. A new magnetically shielded thruster is designed to solve this issue.
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 Fundamentals of Electric Propulsion written by Dan M. Goebel and published by John Wiley & Sons. This book was released on 2023-10-25 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Electric Propulsion Understand the fundamental basis of spaceflight with this cutting-edge guide As spacecraft engineering continues to advance, so too do the propulsion methods by which human beings can seek out the stars. Ion thrusters and Hall thrusters have been the subject of considerable innovation in recent years, and spacecraft propulsion has never been more efficient. For professionals within and adjacent to spacecraft engineering, this is critical knowledge that can alter the future of space flight. Fundamentals of Electric Propulsion offers a thorough grounding in electric propulsion for spacecraft, particularly the features and mechanisms underlying Ion and Hall thrusters. Updated in the light of rapidly expanding knowledge, the second edition of this essential guide detailed coverage of thruster principles, plasma physics, and more. It reflects the historic output of the legendary Jet Propulsion Laboratory and promises to continue as a must-own volume for spacecraft engineering professionals. Readers of the second edition of Fundamentals of Electric Propulsion readers will also find: Extensive updates to chapters covering hollow cathodes and Hall thrusters, based on vigorous recent research New sections covering magnetic shielding, cathode plume instabilities, and more Figures and homework problems in each chapter to facilitate learning and retention Fundamentals of Electric Propulsion is an essential work for spacecraft engineers and researchers working in spacecraft propulsion and related fields, as well as graduate students in electric propulsion, aerospace science, and space science courses.
Download or read book Fundamentals of Plasma Physics written by J. A. Bittencourt and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Plasma Physics is a general introduction designed to present a comprehensive, logical and unified treatment of the fundamentals of plasma physics based on statistical kinetic theory, with applications to a variety of important plasma phenomena. Its clarity and completeness makes the text suitable for self-learning and for self-paced courses. Throughout the text the emphasis is on clarity, rather than formality, the various derivations are explained in detail and, wherever possible, the physical interpretations are emphasized. The mathematical treatment is set out in great detail, carrying out the steps which are usually left to the reader. The problems form an integral part of the text and most of them were designed in such a way as to provide a guideline, stating intermediate steps with answers.
Download or read book Reviews of Plasma Physics written by Vitaly D. Shafranov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews of Plasma Physics, Volume 23, presents two high quality reviews from the cutting-edge of Russian plasma physics research: "Plasma Models of Atom and Radiative-Collisional Processes", by V.A. Astapenko, L.A. Bureyeva, V.S. Lisitsa, is devoted to a unified description of the atomic core polarization effects in the free-free, free-bound and bound-bound transitions of the charged particles in the field of multielectron atom. "Asymptotic Theory of Charge Exchange And Mobility Processes for Atomic Ions" by B.M. Smirnov reviews the process of resonant charge exchange, and also the transport processes (mobility and diffusion coefficients) for ions in parent gases which are determined by resonant electron transfer.
Download or read book Development and Characterization of High efficiency High specific Impulse Xenon Hall Thrusters written by Richard Robert Hofer and published by . This book was released on 2004 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Topics in Plasma Physics written by Sukhmander Singh and published by BoD – Books on Demand. This book was released on 2020-11-19 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is planned to introduce the advances topics of plasma physics for research scholars and postgraduate students. This book deals with basic concepts in plasma physics, non-equilibrium plasma modeling, space plasma applications, and plasma diagnostics. It also provides an overview of the linear and nonlinear aspects of plasma physics. Chapters cover such topics as plasma application in space propulsion, microwave–plasma interaction, plasma antennas, solitary waves, and plasma diagnostic techniques.
Download or read book Plasma Physics written by Alexander Piel and published by Springer. This book was released on 2017-09-07 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: The enlarged new edition of this textbook provides a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The novel fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a concise description of modern plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple and emphasizes the underlying concepts. The guidelines of plasma physics are illustrated by a host of practical examples, preferentially from plasma diagnostics. There, Langmuir probe methods, laser interferometry, ionospheric sounding, Faraday rotation, and diagnostics of dusty plasmas are discussed. Though primarily addressing students in plasma physics, the book is easily accessible for researchers in neighboring disciplines, such as space science, astrophysics, material science, applied physics, and electrical engineering. This second edition has been thoroughly revised and contains substantially enlarged chapters on plasma diagnostics, dusty plasmas and plasma discharges. Probe techniques have been rearranged into basic theory and a host of practical examples for probe techniques in dc, rf, and space plasmas. New topics in dusty plasmas, such as plasma crystals, Yukawa balls, phase transitions and attractive forces have been adopted. The chapter on plasma discharges now contains a new section on conventional and high-power impulse magnetron sputtering. The recently discovered electrical asymmetry effect in capacitive rf-discharges is described. The text is based on an introductory course to plasma physics and advanced courses in plasma diagnostics, dusty plasmas, and plasma waves, which the author has taught at Kiel University for three decades. The pedagogical approach combines detailed explanations, a large number of illustrative figures, short summaries of the basics at the end of each chapter, and a selection of problems with detailed solutions.
Download or read book Investigating Newly Discovered Oscillation Modes in Magnetically Shielded Hall Effect Thrusters Utilizing High Speed Diagnostics written by Matthew Joseph Baird and published by . This book was released on 2020 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetically shielded Hall effect thrusters (MSHETs) are a variant of Hall effect thrusters (HET) that provide the favorable thrust-to-power ratio and high specific impulse of traditional stationary plasma type (STP) HETs but with an extremely long lifetime. MSHETs exhibit unique discharge plasma oscillations compared to traditional unshielded HETs. In this study, measurements of plasma oscillations in the state-of-the-art 12.5 kW Hall Effect Rocket with Magnetic Shielding (HERMeS) were obtained at various discharge voltages while holding other operation parameters constant. Data were collected using high-speed imaging, voltage, current, and plasma probes. The thruster exhibits two dominant oscillation modes within the discharge channel. The first mode is characterized as broadband turbulent oscillation in discharge current, and the second mode is a sinusoidal-like oscillation in discharge current. The oscillations in the discharge channel for both modes are predominantly global throughout the entire discharge and plume. The centrally mounted cathode exhibits a combination of global and localized "spoke" oscillation modes in the ExB direction. Discrete Fourier Transform (DFT) analysis of the high-speed data show the frequency and spoke number dependent dynamic coupling behaviors between the discharge channel and cathode. Moreover, the shape of the cathode mode was quantified at each operating condition using a phase surface analysis technique of the high-speed imaging data. Data from high-speed plasma probes show that oscillations in the cathode permeate into the discharge channel and could be, in part, responsible for driving oscillations in the discharge channel. A novel technique for reconstructing temporally resolved ion energy distribution functions (IEDF(t)) was developed and tested on several plasma sources. This method, called the high-speed retarding potential analyzer (HSRPA), combines a retarding potential analyzer and a high-speed transimpedance amplifier with an empirical transfer function technique previously employed in the spatiotemporal reconstruction of high-speed Langmuir probe data. The analysis technique was successful in reconstructing the IEDF(t) of a modulated gridded ion source and of a 200-W laboratory Hall thruster. The HSRPA was less effective when used to collect IEDF(t) data in the high polar angle regions of the HERMeS thruster plume, but it was able to provide ion energy dependent spectral content. The HSRPA developed was a preliminary proof-of-concept that worked successfully and with subtle improvements would provide a powerful diagnostic tool for enlightening further studies of plasma oscillations in MSHETs.
Download or read book Deep Space Propulsion written by K. F. Long and published by Springer Science & Business Media. This book was released on 2011-11-25 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: The technology of the next few decades could possibly allow us to explore with robotic probes the closest stars outside our Solar System, and maybe even observe some of the recently discovered planets circling these stars. This book looks at the reasons for exploring our stellar neighbors and at the technologies we are developing to build space probes that can traverse the enormous distances between the stars. In order to reach the nearest stars, we must first develop a propulsion technology that would take our robotic probes there in a reasonable time. Such propulsion technology has radically different requirements from conventional chemical rockets, because of the enormous distances that must be crossed. Surprisingly, many propulsion schemes for interstellar travel have been suggested and await only practical engineering solutions and the political will to make them a reality. This is a result of the tremendous advances in astrophysics that have been made in recent decades and the perseverance and imagination of tenacious theoretical physicists. This book explores these different propulsion schemes – all based on current physics – and the challenges they present to physicists, engineers, and space exploration entrepreneurs. This book will be helpful to anyone who really wants to understand the principles behind and likely future course of interstellar travel and who wants to recognizes the distinctions between pure fantasy (such as Star Trek’s ‘warp drive’) and methods that are grounded in real physics and offer practical technological solutions for exploring the stars in the decades to come.
Download or read book Materials and Processes written by Barrie D. Dunn and published by Springer. This book was released on 2015-12-29 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this book is to assist scientists and engineers select the ideal material or manufacturing process for particular applications; these could cover a wide range of fields, from light-weight structures to electronic hardware. The book will help in problem solving as it also presents more than 100 case studies and failure investigations from the space sector that can, by analogy, be applied to other industries. Difficult-to-find material data is included for reference. The sciences of metallic (primarily) and organic materials presented throughout the book demonstrate how they can be applied as an integral part of spacecraft product assurance schemes, which involve quality, material and processes evaluations, and the selection of mechanical and component parts. In this successor edition, which has been revised and updated, engineering problems associated with critical spacecraft hardware and the space environment are highlighted by over 500 illustrations including micrographs and fractographs. Space hardware captured by astronauts and returned to Earth from long durations in space are examined. Information detailed in the Handbook is applicable to general terrestrial applications including consumer electronics as well as high reliability systems associated with aeronautics, medical equipment and ground transportation. This Handbook is also directed to those involved in maximizing the relia bility of new materials and processes for space technology and space engineering. It will be invaluable to engineers concerned with the construction of advanced structures or mechanical and electronic sub-systems.
Download or read book Micro Newton Thruster Development written by Franz Georg Hey and published by Springer. This book was released on 2018-03-01 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: Franz Georg Hey summarises the development and testing of a micro-Newton thrust balance, as well as the downscaling of a High Efficiency Multistage Plasma Thruster to micro-Newton thrust levels. The balance is tailored to fully characterise thruster candidates for the space based gravitational wave detector LISA. Thus, thrust noise measurements in sub-micro-Newton regime can be performed in the overall LISA bandwidth. The downscaled thruster can be operated down to serval tens of micro-Newton with a comparably high specific impulse. About the Author Franz Georg Hey works as mechanical, thermal, propulsion architect and technical lead of the micro‐Newton propulsion laboratory of Europe’s leading air and spacecraft manufacturer. The author is participating on major programmes for future satellite and electric propulsion development. The author’s research is performed in close collaboration with the Dresden University of Technology, the University of Bremen and the DLR Bremen.
Download or read book Clustering of Hall Effect Thrusters for High power Electric Propulsion Applications written by Brian Eric Beal and published by . This book was released on 2004 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Taming Liquid Hydrogen written by Virginia Parker Dawson and published by . This book was released on 2004 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shipboard Propulsion Power Electronics and Ocean Energy written by Mukund R. Patel and published by CRC Press. This book was released on 2012-02-17 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shipboard Propulsion, Power Electronics, and Ocean Energy fills the need for a comprehensive book that covers modern shipboard propulsion and the power electronics and ocean energy technologies that drive it. With a breadth and depth not found in other books, it examines the power electronics systems for ship propulsion and for extracting ocean energy, which are mirror images of each other. Comprised of sixteen chapters, the book is divided into four parts: Power Electronics and Motor Drives explains basic power electronics converters and variable-frequency drives, cooling methods, and quality of power Electric Propulsion Technologies focuses on the electric propulsion of ships using recently developed permanent magnet and superconducting motors, as well as hybrid propulsion using fuel cell, photovoltaic, and wind power Renewable Ocean Energy Technologies explores renewable ocean energy from waves, marine currents, and offshore wind farms System Integration Aspects discusses two aspects—energy storage and system reliability—that are essential for any large-scale power system This timely book evolved from the author’s 30 years of work experience at General Electric, Lockheed Martin, and Westinghouse Electric and 15 years of teaching at the U.S. Merchant Marine Academy. As a textbook, it is ideal for an elective course at marine and naval academies with engineering programs. It is also a valuable reference for commercial and military shipbuilders, port operators, renewable ocean energy developers, classification societies, machinery and equipment manufacturers, researchers, and others interested in modern shipboard power and propulsion systems. The information provided herein does not necessarily represent the view of the U.S. Merchant Marine Academy or the U.S. Department of Transportation. This book is a companion to Shipboard Electrical Power Systems (CRC Press, 2011), by the same author.
