Download or read book Investigations of Probe Induced Perturbations in a Hall Thruster written by D. Staack and published by . This book was released on 2002 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigations of Probe Induced Perturbations in a Hall Thruster written by D. Staack and published by . This book was released on 2002 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Results from Internal and Very Near Field Plasma Diagnostics of a High Specific Impulse Hall Thruster written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Floating potential and ion current density measurements were taken on the laboratory model NASA-173Mv2 in order to improve understanding of the physical processes affecting Hall thruster performance at high specific impulse. Floating potential was measured on discharge chamber centerline over axial positions spanning 10 mm from the anode to 100 mm downstream of the exit plane. Ion current density was mapped radially up to 300 mm from thruster centerline over axial positions in the very-near-field (10 to 250 mm from the exit plane). All data were collected using a planar probe in conjunction with a high-speed translation stage to minimize probe-induced thruster perturbations. Measurements of floating potential at a xenon flow rate of 10 mg/s have shown that the acceleration layer moved upstream 3 1 mm when the voltage increased from 300 to 600 V. The length of the acceleration layer was 14 2 mm and was approximately constant with voltage and magnetic field. Ion current density measurements indicated the annular ion beam crossed the thruster centerline 163 mm downstream of the exit plane. Radial integration of the ion current density at the cathode plane provided an estimate of the ion current fraction. At 500 V and 5 mg/s, the ion current fraction was calculated as 0.77. Hofer, Richard R. and Gallimore, Alec D. and Jacobson, David (Technical Monitor) Glenn Research Center NASA/CR-2003-212604, E-14162, IEPC-2003-037
Download or read book 38th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 02 4100 02 4149 written by and published by . This book was released on 2002 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigations with a 5 kW Class Laboratory Model Closed Drifted Hall Thruster written by and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final technical report summarizes research conducted at the Plasmadynamics and Electric Propulsion Laboratory (PEPL) to characterize the internal and plume plasma of a closed-drift Hall thruster (CDT). The project was composed of the following segments: 1) a 5-kW-class CDT (P5) was built and characterized in terms of performance and plume divergence; 2) the molecular-beam mass spectrometer (MBMS) was used to measure the ion energy distribution finction and charge state throughout the PS plume; 3) laser-induced fluorescence was used to measure the ion velocity and temperature in the near-field plume; 4) a 35 GHz microwave interferometer was developed to measure plasma oscillations and electron density in the plume; and 5) the near-field and internal plasma of the PS were characterized using the High-speed Axial Reciprocating Probe (HARP) system developed for this effort. The HARP system enabled, for the first time, the insertion and removal of probes from a CDT discharge channel while minimizing perturbation to thruster operation. The magnetic field, electron temperature, ion number density, plasma and floating potential, and Hall current were mapped throughout the PS discharge chamber at two operating conditions. Thruster perturbation, determined by monitoring discharge current, was less than 10% for the majority of measurements.
Download or read book Investigations of an Environmentally Induced Long Duration Hall Thruster Start Transient PREPRINT written by and published by . This book was released on 2006 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A long duration Hall thruster start transient is produced by exposure of the thruster to ambient laboratory atmosphere. This behavior was first observed during operation of a cluster of four 200 W BHT-200 Hall effect thrusters where large anode discharge fluctuations, visible as increased anode current and a diffuse plume structure, occurred in an apparently random manner. During operation of a single thruster, the start transient appears as a quickly rising and later smoothly decaying elevated anode current with a diffuse plume that persists for less than 500 seconds. The start transient is characterized by severe 18 kHz oscillations that dominate the anode discharge. This contrasts sharply with typical steady state behavior of a strong DC component overlaid with a low amplitude 25 kHz component. The source of the plasma oscillations has been isolated to the discharge chamber. The oscillations of the anode current appear to be due to the evolution of water previously hydrated onto the surface layer of the boron nitride acceleration channel insulator during exposure of the Hall effect thruster to ambient atmosphere. Once all available water has been driven from the insulator surface by plasma heating, the discharge fluctuations do not reappear.
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 A Preliminary Investigation of Hall Thruster Technology written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-21 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: A three-year NASA/BMDO-sponsored experimental program to conduct performance and plume plasma property measurements on two Russian Stationary Plasma Thrusters (SPTs) has been completed. The program utilized experimental facilitates at the University of Michigan's Plasmadynamics and Electric Propulsion Laboratory (PEPL). The main features of the proposed effort were as follows: (1) Characterized Hall thruster (and arcjet) performance by measuring ion exhaust velocity with probes at various thruster conditions; (2) Used a variety of probe diagnostics in the thruster plume to measure plasma properties and flow properties including T(sub e) and n(sub e) ion current density and ion energy distribution, and electric fields by mapping plasma potential; (3) Used emission spectroscopy to identify species within the plume and to measure electron temperatures. A key and unique feature of our research was our collaboration with Russian Hall thruster researcher Dr. Sergey A Khartov, Deputy Dean of International Relations at the Moscow Aviation Institute (MAI). His activities in this program included consulting on and participation in research at PEPL through use of a MAI-built SPT and ion energy probe. Gallimore, Alec D. Glenn Research Center NAG3-1504...
Download or read book Probe Studies of a Hall Thruster at Low Voltages written by Jerry L. Ross and published by . This book was released on 2011 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low perturbation Interrogation of the Internal and Near field Plasma Structure of a Hall Thruster Using a High speed Probe Positioning System written by James Matthew Haas and published by . This book was released on 2001 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 41st AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 10 13 July 2005 Tucson Arizona 05 4350 05 4399 written by and published by . This book was released on 2005 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurements of Plasma Potential Distribution in Segmented Electrode Hall Thruster written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Use of a segmented electrode placed at the Hall thruster exit can substantially reduce the voltage potential drop in the fringing magnetic field outside the thruster channel. In this paper, we investigate the dependence of this effect on thruster operating conditions and segmented electrode configuration. A fast movable emissive probe is used to measure plasma potential in a 1 kW laboratory Hall thruster with semented electrodes made of a graphite material. Relatively small probe-induced perturbations of the thruster discharge in the vicinity of the thruster exit allow a reasonable comparison of the measured results for different thruster configurations. It is shown that the plasma potential distribution is almost not sensitive to changes of the electrode potential, but depends on the magnetic field distribution and the electrode placement.
Download or read book Experimental Investigation of a Hall current Thruster written by and published by . This book was released on 1983 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Comprehensive Investigation of the Role of Vacuum Facility Pressure on High Power Hall Thruster Testing written by and published by . This book was released on 2002 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: Closed-Drift Hall thrusters (CDTs) have great potential in satisfying many of the spacecraft propulsion needs of the United States Air Force for the next several decades. Its combination of high specific impulse, high thrust efficiency, and high thrust density makes it very attractive for a number of earth-orbit missions. However, due to the wide range of facilities used in CDT testing, it is difficult for researchers to make adequate comparisons between data sets because of both dissimilar instrumentation and backpressures. Thus, a tool is needed that allows researchers to obtain relevant plume data for a variety of chambers and backpressures. To this end, our work for this one-year effort has focused on studying the effectiveness of collimated Faraday probes in obtaining ion current density profiles of CDTs. A collimated probe is attractive because it offers the possibility of obtaining the true ion current density profile regardless of facility pumping speed by filtering low-energy charge-exchange collisions ions from the collector. We compare the ion current density profiles obtained simultaneously with collimated and 'nude' probes one meter from a CDT, at two facility pumping speeds and at thruster power levels between 1.5 and 5.0 kW.
Download or read book Ion Voltage Diagnostics in the Far Field Plume of a High Specific Impulse Hall Thruster written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of the magnetic field and discharge voltage on the far-field plume of the NASA 173Mv2 laboratory-model Hall thruster were investigated. A cylindrical Langmuir probe was used to measure the plasma potential and a retarding potential analyzer was employed to measure the ion voltage distribution. The plasma potential was affected by relatively small changes in the external magnetic field, which suggested a means to control the plasma surrounding the thruster. As the discharge voltage increased, the ion voltage distribution showed that the acceleration efficiency increased and the dispersion efficiency decreased. This implied that the ionization zone was growing axially and moving closer to the anode, which could have affected thruster efficiency and lifetime due to higher wall losses. However, wall losses may have been reduced by improved focusing efficiency since the total efficiency increased and the plume divergence decreased with discharge voltage. Hofer, Richard R. and Haas, James M. and Gallimore, Alec D. Glenn Research Center NASA/CR-2003-212895, AIAA Paper 2003-4556, E-14313
Download or read book 37th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit written by and published by . This book was released on 2001 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of a Pulsed Plasma Thruster for Atmospheric Applications written by Manuel Azuara Rosales and published by . This book was released on 2020 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: To date, the controlled access to terrestrial atmospheric altitudes of more than 20 km is limited with current technology. This is because at such altitudes, the background gas density is too low for conventional blade-based propellers to operate, and too high for most in-space electric propulsion systems. This research aims to investigate the Pulsed Plasma Thruster technology for atmospheric applications, at a background gas pressure of less than 50 Torr, corresponding to terrestrial atmospheric altitudes of more than 20 km. Because the system operates in a highly collisional regime, three acceleration mechanisms are identified, 1) due to ion-neutral collisions, 2) due to the J x B force, and 3) electrostatic acceleration. A theoretical model to obtain the thrust-to-power ratio of a Pulsed Plasma Thruster for atmospheric applications is presented and validated experimentally using a pendulum-based thrust stand, a quadruple Langmuir probe, and a B-dot probe. A proposed Air-Breathing Pulsed Plasma Thruster was investigated, and based on the experimental results, an analytical approach to determine whether the system can sustain an aircraft at the aforementioned altitudes is presented, and experimentally demonstrated through three in-field tests, consisting on launching in-house designed and built aircraft to the stratosphere using high-altitude burst balloons.
