Download or read book Preliminary Plume Characterization of a Low Power Hall Thruster Cluster written by and published by . This book was released on 2002 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to understand the technical issues related to running multiple Hall effect thrusters in close proximity to each other, testing of a cluster of four Busek BHT-200-X3 devices has begun in Chamber 6 at the Air Force Research Laboratory. Preliminary measurements have shown that the variations in the discharge currents of the four thrusters are synchronized, possibly due to cross talk through the thruster plumes. Measurements of plasma density, electron temperature, and plasma potential in the thruster plumes obtained using a triple Langmuir probe are presented. Anomalously high electron temperatures were recorded along the centerline of each thruster. Collisionless, magnetosonic shock waves induced by the ion-ion two-stream instability are proposed as a possible cause of the high temperatures. The unperturbed ion velocity distribution along the centerline of a Hall thruster is shown to be unstable and a simple geometric model is presented to illustrate the qualitative changes in plasma properties expected across the proposed shock. Estimates using this model show that relatively large changes in electron temperature are consistent with small changes in electron number density across a shock. Qualitative arguments are presented indicating that collisionless shocks are unlikely to form as a result of clustering multiple thrusters. In an effort to understand the technical issues related to running multiple Hall effect thrusters in close proximity to each other, testing of a cluster of four Busek BHT-200-X3 devices has begun in Chamber 6 at the Air Force Research Laboratory. Preliminary measurements have shown that the variations in the discharge currents of the four thrusters are synchronized, possibly due to cross talk through the thruster plumes. Measurements of plasma density, electron temperature, and plasma potential in the thruster plumes obtained using a triple Langmuir probe are presented.
Download or read book Preliminary Characterization of a Low Power End hall Thruster written by Alec D. Gallimore and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preliminary Study of Arcjet Neutralization of Hall Thruster Clusters Postprint written by and published by . This book was released on 2007 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clustered Hall thrusters have emerged as a favored choice for extending Hall thruster options to very high powers (50 kW - 150 kW). This paper examines the possible use of an arcjet to neutralize clustered Hall thrusters, as the hybrid arcjet-Hall thruster concept can fill a performance niche amongst available propulsion options. We examine missions on which this hybrid concept would be a competitive or favored thruster option, report on fundamental experiments to understand how much electron current can be drawn to a surrogate anode from the plume of low power arcjets operating on hydrogen and helium, and then demonstrate the first successful operation of a low power Hall thruster-arcjet neutralizer package. In the surrogate anode studies, we find that the drawing of current from the arcjet plume has only a weak effect on overall arcjet performance (thrust), with a slight decrease in arc voltage with increased extracted current. A single Hall thruster - arcjet neutralizer package was constructed for the hybrid concept demonstration. The arcjet operated at very low powers ( - 70-120W) on helium, at a mass flow rate of 4.5 mg/s, and was able to effectively neutralize the - 200 -900W xenon Hall thruster causing little measurable departure from the hollow-cathode neutralized Hall thruster VI characteristics up to 250V. At higher helium mass flow rates, the Hall discharge current is slightly perturbed from its expected values, due most likely to the ingestion of helium. Further developments of the hybrid concept to clustered configurations and higher powers will require a vacuum facility that can pump tens of milligrams of helium while maintaining the low pressures needed for normal xenon Hall thruster operation.
Download or read book Preliminary Far field Plume Sputtering Characterization of the Stationary Plasma Thruster SPT 100 written by and published by . This book was released on 1994 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 39th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit July 20 23 2003 Huntsville Alabama 03 5150 03 5199 written by and published by . This book was released on 2003 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comprehensive Investigation of Facility Effects on the Testing of High Power Monolithic and Clustered Hall Thruster Systems written by and published by . This book was released on 2006 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research focuses on understanding the relationship between facility background pressure and Hall effect thruster/cluster performance and plume characteristics. It is difficult for researchers to make adequate comparisons between data sets because of both differences in instrumentation and back pressures due to the wide range of facilities used in Hall thruster testing. Thus, tools are needed that allow researchers to obtain relevant plume and performance data for a variety of chambers and back pressures. This research is divided into three parts. The first is the development of a technique for calibrating a vacuum chamber in terms of pressure. The second is an investigation of facility effects; i.e., how elevated facility back pressure affects thruster performance, plume plasma parameters, and plume diagnostics. The third portion of this research is an investigation of the performance and plume characteristics of a cluster of UM/AFRL P5 5 kw Hall thrusters operated over a wide range of facility back pressures.
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 Plume Characterization of Busek 600W Hall Thruster written by Duc Minh Bui and published by . This book was released on 2012 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Theoretical Characterization of a Hall Thruster Plume written by Yassir Azziz and published by . This book was released on 2007 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) However, comparison of plume simulation and experimental results at a non-zero background pressure showed deficiencies in the collision model of the plume simulation. An analytical expression for current density obtained using a elf-similar plume model was compared to extrapolated current density at zero pressure and showed good agreement. In addition, an analytical model derived for current density of source ion collisions with neutrals was consistent with experimental measurements and confirms the deficiencies in the simulation's collision model. In summary, experimental, numerical and analytical results indicate that the method of determining in-orbit plume divergence from laboratory measurements is valid and can be used to integrate Hall thrusters with the spacecraft.
Download or read book 41st AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 10 13 July 2005 Tucson Arizona 05 3650 05 3699 written by and published by . This book was released on 2005 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Clustering Multiple Hall Thrusters on Plasma Plume Properties written by and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of Hall thrusters have been proposed as a means of achieving electric propulsion systems capable of operating at very high power levels. To facilitate testing in existing vacuum facilities initial tests have focused on a cluster of low-power Busek BHT-2OO-X3 Hall thrusters. A combination of triple Laugmuir probes and floating emissive probes has been used to study the effects of multi-thruster operation on the electron number density, electron temperature, and plasma potential in the plasma plume. The resultant number density is shown to be a result of linear superposition of the plumes of individual thrusters while the electron temperature in the cluster plume is measured to be slightly higher than that caused by operation of a single thruster. The plasma potential downstream of the cluster is shown to obey the Boltzmann relation. In the region between the thrusters the plasma potential increases as a function of downstream distance and may result in reflection of some low-energy charge exchange ions back toward the cluster. A mechanism that may lead to slightly reduced ion beam divergence through focusing of ions directed toward the thruster centerline is discussed.
Download or read book Plume Characteristics of the Busek 600 W Hall Thruster written by and published by . This book was released on 2006 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: To better characterize the potential impacts of the operation of a Busek Company, Inc. BHT-HD-600 laboratory Hall thruster on spacecraft, a number of plume properties have been measured. These include current density using a Faraday probe, ion energy distribution using a retarding potential analyzer, and ion species fractions using an E x B probe. The BHT-HD-600 Hall thruster is a nominally 600 W xenon Hall thruster developed by Busek Co. Inc. for the U.S. Air Force Research Laboratory. Plume characterization of Hall thrusters is required to fully understand the impacts of thruster operation on spacecraft. Much of these plume data are vital inputs for numerical models that can then be applied to estimate the effect of the energetic plume on complex spacecraft geometries. Early measurement of plume properties, such as plume divergence, ion energy distribution, and species fractions, aids the timely transfer of Hall thruster technology to the user. The plume's ion beam was characterized by measurement of ion current density radial profiles, ion energy spectra and ion species fraction distributions. Measurements were recorded at +or- 90 degrees off thruster centerline at 60 cm from the discharge. It was determined slight variations in anode potential and mass-flow produced a measurable effect on ion current density and plume divergence, experimentally showing an increase or decrease of +or- 15-20%. Ionic energy spectra demonstrated both inelastic and elastic scattering within the plume. The measurements reveal significant populations of multiply-charged ions in the plume. E x B probe measurements show surprisingly ion species fraction angle dependence.
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 Pulsed Plasma Thruster Plume Characterization of Ion Species Using a Gridded Energy Analyzer written by Krystal Marie Parker and published by . This book was released on 2002 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 39th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit July 20 23 2003 Huntsville Alabama 03 4850 03 4899 written by and published by . This book was released on 2003 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effects of Cathode Configuration on Hall Thruster Cluster Plume Properties PREPRINT written by and published by . This book was released on 2005 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of Hall thrusters are being considered for use on a variety of missions requiring electric propulsion systems capable of operating at power levels in excess of the current state of the art. One of the key factors to be considered in determining the optimum cluster architecture is the configuration of the electron-emitting cathode(s). This work presents experimentally determined plume properties and discharge current characteristics obtained with multiple thrusters coupled to a single cathode. Spatially resolved plasma density, electron temperature, and plasma potential data are presented during both single thruster and cluster operation. Measurements taken in this configuration are compared to previously published data obtained with each thruster coupled to its own independent cathode. Significant differences between the two configurations are noted and explained. Additionally, critical plasma parameters in the cluster plume are shown to be strongly influenced by the location of the hollow cathode.
