Download or read book Efficiency Analysis 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 2018-06-21 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance and plasma measurements of the high-specific impulse NASA-173Mv2 Hall thruster were analyzed using a phenomenological performance model that accounts for a partially-ionized plasma containing multiply-charged ions. Between discharge voltages of 300 to 900 V, the results showed that although the net decrease of efficiency due to multiply-charged ions was only 1.5 to 3.0 percent, the effects of multiply-charged ions on the ion and electron currents could not be neglected. Between 300 to 900 V, the increase of the discharge current was attributed to the increasing fraction of multiply-charged ions, while the maximum deviation of the electron current from its average value was only +5/-14 percent. These findings revealed how efficient operation at high-specific impulse was enabled through the regulation of the electron current with the applied magnetic field. Between 300 to 900 V, the voltage utilization ranged from 89 to 97 percent, the mass utilization from 86 to 90 percent, and the current utilization from 77 to 81 percent. Therefore, the anode efficiency was largely determined by the current utilization. The electron Hall parameter was nearly constant with voltage, decreasing from an average of 210 at 300 V to an average of 160 between 400 to 900 V. These results confirmed our claim that efficient operation can be achieved only over a limited range of Hall parameters. Jacobson, David (Technical Monitor) and Hofer, Richard R. and Gallimore, Alec D. Glenn Research Center NASA/CR-2004-213212, E-14720, AIAA Paper 2004-3602

Download or read book Efficiency Analysis of a High Specific Impulse Hall Thruster written by David Jacobson and published by BiblioGov. This book was released on 2013-07 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance and plasma measurements of the high-specific impulse NASA-173Mv2 Hall thruster were analyzed using a phenomenological performance model that accounts for a partially-ionized plasma containing multiply-charged ions. Between discharge voltages of 300 to 900 V, the results showed that although the net decrease of efficiency due to multiply-charged ions was only 1.5 to 3.0 percent, the effects of multiply-charged ions on the ion and electron currents could not be neglected. Between 300 to 900 V, the increase of the discharge current was attributed to the increasing fraction of multiply-charged ions, while the maximum deviation of the electron current from its average value was only +5/-14 percent. These findings revealed how efficient operation at high-specific impulse was enabled through the regulation of the electron current with the applied magnetic field. Between 300 to 900 V, the voltage utilization ranged from 89 to 97 percent, the mass utilization from 86 to 90 percent, and the current utilization from 77 to 81 percent. Therefore, the anode efficiency was largely determined by the current utilization. The electron Hall parameter was nearly constant with voltage, decreasing from an average of 210 at 300 V to an average of 160 between 400 to 900 V. These results confirmed our claim that efficient operation can be achieved only over a limited range of Hall parameters.

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 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 Performance Testing and Internal Probe Measurements of a High Specific Impulse Hall Thruster written by Noah Zachary Warner and published by . This book was released on 2003 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: The BHT-1000 high specific impulse Hall thruster was used for performance testing and internal plasma measurements to support the ongoing development of computational models. The thruster was performance tested in both single and two stage anode configurations. In the single stage configuration, the specific impulse exceeded 3000s at a discharge voltage of 1000V while maintaining a thrust efficiency of 50 percent. Two stage operation produced higher thrust, specific impulse and thrust efficiency than the single stage configuration at most discharge voltages. The thruster thermal warmup was characterized using a thermocouple embedded in the outer exit ring, and the magnetic field topology was investigated using a Gaussmeter. The single stage thruster configuration was outfitted with a series of axially distributed Langmuir probes to determine plasma properties inside the discharge channel. Probe data were taken at discharge voltages between 300-900V. Axial profiles of electron temperature, electron density, and plasma potential were measured and compared to results of a previously developed two dimensional particle-in-cell simulation of the BHT-1000 thruster. The experimental data matched the simulation results well, particularly in profiles of electron temperature and plasma potential at low discharge voltages. The peak electron temperature was shown to depend on discharge voltage through a power law relationship in both the experimental and simulated data. The greatest discrepancies between experimental data and simulation results were found to be in comparisons of electron density, where it appears that the simulation may be "smearing" the plasma over too wide of an axial region. Hypotheses for this behavior were discussed along with recommendations for future work.

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 A Hall Thruster Performance Model Incorporating the Effects of a Multiply Charged Plasma written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-03 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Hall thruster performance model that predicts anode specific impulse, anode efficiency, and thrust is discussed. The model is derived as a function of a voltage loss parameter, an electron loss parameter, and the charge state of the plasma. Experimental data from SPT and TAL type thrusters up to discharge powers of 21.6 kW are used to determine the best fit for model parameters. General values for the model parameters are found, applicable to high power thrusters and irrespective of thruster type. Performance of a 50 kW thruster is calculated for an anode specific impulse of 2500 seconds or a discharge current of 100 A. Hofer, Richard R. and Jankovsky, Robert S. Glenn Research Center NASA/TM-2002-211214, E-13066, NAS 1.15:211214, AIAA Paper 2001-3322

Download or read book Standardization of Hall Thruster Efficiency Analysis Methodology and Historical Perspective written by and published by . This book was released on 2008 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rocket power efficiency equation was analytically decomposed to explicitly account for the effects of energy conversion losses, plume divergence, and the velocity distribution function of the propellant jet. In this approach, thruster efficiency is the product of (1) energy efficiency and (2) propellant utilization efficiency. Energy efficiency is expressed as the product of voltage utilization efficiency and current utilization efficiency, and incorporates losses from Joule heating, radiation, and ionization processes. Energy efficiency contains no information about the vector properties of the jet. Propellant utilization efficiency incorporates losses from plume divergence and ion jet composition, and is unity for 100% ionization to a single ion species whose velocity vectors are directed along the thrust axis. The efficiency architecture is derived from first principles and is applicable to all propulsion employing electrostatic acceleration, including Hall thrusters and ion engines. The analysis is compared to past methodologies and is illustrated with thrust and far-field plume measurements of a laboratory Hall thruster.

Download or read book A Hall Thruster Performance Model Incorporating the Effects of a Multiply Charged Plasma written by Richard R. Hofer and published by . This book was released on 2002 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 The Influence of Current Density and Magnetic Field Topography in Optimizing the Performance Divergence and Plasma Oscillations of High Specific Impulse Hall Thrusters 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 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies of xenon Hall thrusters have shown peak efficiencies at specific impulses of less than 3000 s. This was a consequence of modern Hall thruster magnetic field topographies, which have been optimized for 300 V discharges. On-going research at the NASA Glenn Research Center is investigating this behavior and methods to enhance thruster performance. To conduct these studies, a laboratory model Hall thruster that uses a pair of trim coils to tailor the magnetic field topography for high specific impulse operation has been developed. The thruster-the NASA-173Mv2 was tested to determine how current density and magnetic field topography affect performance, divergence, and plasma oscillations at voltages up to 1000 V. Test results showed there was a minimum current density and optimum magnetic field topography at which efficiency monotonically increased with voltage. At 1000 V, 10 milligrams per second the total specific impulse was 3390 s and the total efficiency was 60.8%. Plume divergence decreased at 400-1000 V, but increased at 300-400 V as the result of plasma oscillations. The dominant oscillation frequency steadily increased with voltage, from 14.5 kHz at 300 V, to 22 kHz at 1000 V. An additional oscillatory mode in the 80-90 kHz frequency range began to appear above 500 V. The use of trim coils to modify the magnetic field improved performance while decreasing plume divergence and the frequency and magnitude of plasma oscillations. Hofer, Richard R. and Jankovsky, Robert S. Glenn Research Center NASA/TM-2003-212605, E-14163, IEPC-2003-142

Download or read book Ion Voltage Diagnostics in the Far Field Plume of a High Specific Impulse Hall Thruster written by Richard R. Hofer and published by BiblioGov. This book was released on 2013-06 with total page 22 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.

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 Performance Test Results of the Nasa 457m V2 Hall Thruster written by George C. Soulas and published by BiblioGov. This book was released on 2013-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance testing of a second generation, 50 kW-class Hall thruster labeled NASA-457M v2 was conducted at the NASA Glenn Research Center. This NASA-designed thruster is an excellent candidate for a solar electric propulsion system that supports human exploration missions. Thruster discharge power was varied from 5 to 50 kW over discharge voltage and current ranges of 200 to 500 V and 15 to 100 A, respectively. Anode efficiencies varied from 0.56 to 0.71. The peak efficiency was similar to that of other state-of-the-art high power Hall thrusters, but outperformed these thrusters at lower discharge voltages. The 0.05 to 0.18 higher anode efficiencies of this thruster compared to its predecessor were primarily due to which of two stable discharge modes the thruster was operated. One stable mode was at low magnetic field strengths, which produced high anode efficiencies, and the other at high magnetic fields where its predecessor was operated. Cathode keeper voltages were always within 2.1 to 6.2 V and cathode voltages were within 13 V of tank ground during high anode efficiency operation. However, during operation at high magnetic fields, cathode-to-ground voltage magnitudes increased dramatically, exceeding 30 V, due to the high axial magnetic field strengths in the immediate vicinity of the centrally-mounted cathode. The peak thrust was 2.3 N and this occurred at a total thruster input power of 50.0 kW at a 500 V discharge voltage. The thruster demonstrated a thrust-to-power range of 76.4 mN/kW at low power to 46.1 mN/kW at full power, and a specific impulse range of 1420 to 2740 s. For a discharge voltage of 300 V, where specific impulses would be about 2000 s, thrust efficiencies varied from 0.57 to 0.63.

Download or read book Performance Evaluation of a 50kW Hall Thruster written by David T. Jacobson and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA s Hall Thruster Program written by Robert S. Jankovsky and published by . This book was released on 2001 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multimode High Specific Impulse Hall Thruster Technology written by G. W. Butler and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: