Download or read book Instrument Development and Plasma Measurements on a 200 watt Hall Thruster Plume written by Yassir Azziz and published by . This book was released on 2003 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plume and Discharge Plasma Measurements of an NSTAR type Ion Thruster written by John E. Foster and published by . This book was released on 2000 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Preliminary Investigation of Hall Thruster Technology written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-28 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 Plasma Potential and Langmuir Probe Measurements in the Near Field Plume of the Nasa 300m Hall Thruster written by Daniel A. Herman and published by BiblioGov. This book was released on 2013-06 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to aid in the design of high-power Hall thrusters and provide experimental validation for existing modeling efforts, plasma potential and Langmuir probe measurements were performed in the near-field plume of the NASA 300M Hall thruster. A probe array consisting of a Faraday probe, Langmuir probe, and emissive probe was used to interrogate the plume from approximately 0.1 - 2.0 DT, m downstream of the thruster exit plane at four operating conditions: 300 V, 400 V, and 500 V at 20 kW as well as 300 V at 10 kW. Results show that the acceleration zone and high-temperature region were contained within 0.3 DT, m from the exit plane at all operating conditions. Isothermal lines were shown to strongly follow magnetic field lines in the nearfield, with maximum temperatures ranging from 19 - 27 eV. The electron temperature spatial distribution created large drops in measured floating potentials in front of the magnetic pole surfaces where the plasma density was small, which suggests strong sheaths at these surfaces. The data taken have provided valuable information for future design and modeling validation, and complements ongoing internal measurement efforts on the NASA 300
Download or read book Pulsed Plasma Thruster Plume Study Symmetry and Impact on Spacecraft Surfaces written by Lynn A. Arrington and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transport property and Mass Spectral Measurements in the Plasma Exhaust Plume of a Hall effect Space Propulsion System written by Lyon Bradley King and published by . This book was released on 1998 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plasma Properties in the Plume of a Hall Thruster Cluster written by and published by . This book was released on 2003 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hall thruster cluster is an attractive propulsion approach for spacecraft requiring very high-power electric propulsion systems. This article presents plasma density, electron temperature, and plasma potential data collected with a combination of triple Langmuir probes and floating emissive probes in the plume of a low-power, four-engine Hall thruster cluster. Simple analytical formulas are introduced that allow these quantities to be predicted downstream of a cluster based solely on the known plume properties of a single thruster. Ion energy distribution functions measured using both a parallel plate electrostatic analyzer and a retarding potential analyzer are presented. A cluster of Hall thrusters is shown to exhibit dramatically different ion energy profiles compared to a single thruster. In particular, clustering causes a significant increase in the fraction of ions at energies below the primary peak in the distribution, most likely due to an increase in elastic scattering and the effects of the unique plasma potential profiles in the cluster plume.
Download or read book Probe Measurements of Plasma Properties Inside an Experimental Hall Thruster written by Y. Raitses and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Numerical Examination of a Hall Thruster Plume Preprint written by and published by . This book was released on 2007 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The plume of a Busek BHT-200 xenon Hall thruster has been characterized through measurements from various plasma electrostatic probes. Ion current flux, plasma potential, plasma density, and electron temperatures were measured from the near-field plume to 60 cm downstream of the exit plane. These experimentally derived measurements were compared to numerical simulations run with the plasma plume code DRACO. A major goal of this study was to determine the fidelity of the DRACO numerical simulation. The effect of background pressure on the thruster plume was also examined using ion current flux measurements at higher than nominal pressure.
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 Plasma Potential and Langmuir Probe Measurements in the Near Field Plume of the Nasa 457mv2 Hall Thruster written by Rohit Shastry 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 NASA Technical Reports Servcr (NTRS) houses half a million publications that are a valuable means of information to researchers, teachers, students, and the general public. These documents are all aerospace related with much scientific and technical information created or funded by NASA. Some types of documents include conference papers, research reports, meeting papers, journal articles and more. This is one of those documents.
Download or read book Preliminary Results of Plasma Flow Measurements in a 2 KW Segmented Hall Thruster written by Y. Raitses and published by . This book was released on 2003 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plasma Measurements in a 100W Cylindrical Hall Thruster written by A. Smirnov and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pulsed Plasma Thruster Plume Measurements Using a Triple Langmuir Probe Method written by L. Byrne and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interior and Exterior Laser Induced Fluorescence and Plasma Measurements Within a Hall Thruster Postprint written by and published by . This book was released on 2002 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe results of a study of emissive-probe-based plasma potential measurements and laser-induced fluorescence velocimetry of neutral and singly ionized xenon in the plume and interior portions of the acceleration channel of a Hall thruster plasma discharge operating at powers ranging from 250 to 725 W. Axial ion and neutral velocity profiles for four discharge voltage conditions (100, 160, 200, and 250V) are measured as are radial ion velocity profiles in the near-field plume. Axial ion velocity measurements both inside and outside the thruster as well as radial velocity measurements outside the thruster are performed using laser-induced fluorescence with nonresonant signal detection. Neutral axial velocity measurements are similarly performed in the interior of the Hall thruster with resonance fluorescence collection. Optical access to the interior of the Hall thruster is provided by a 1-mm-wide axial slot in the outer insulator wall. The majority of the ion velocity measurements used partially saturated fluorescence to improve the signal-to-noise ratio. Probe-based plasma potential measurements extend from 50 mm outside the thruster exit plane to the near anode region for all but the highest discharge voltage condition. For each condition, the axial electric field is calculated from the plasma potential, and the local electron temperature is determined from the difference between the floating and plasma potentials. These two sets of measurements delineate the structure of the plasma and indicate that the ionization and acceleration regions are somewhat separated. Also, these measurements indicate a region of low electric field near the thruster exit, especially at the higher discharge voltages. This region of near constant potential (low electric field) may be a result of oscillations, which enhance the local plasma conductivity.
Download or read book A Novel Measurment of Net Erosion and Plasma material Interaction in Plasma Thrusters written by Spenser Curtis Guerin and published by . This book was released on 2016 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of plasma thrusters is usually limited not by depletion of the propellant supply, but by erosion of the magnetic circuit from plasma particles bombarding the walls of the acceleration channel leading eventually to catastrophic engine failure. As erosion is the primary failure mode of these systems, understanding the erosion physics, plasma-material interactions (PMI), and the relationship between them is of utmost importance for extending the lifetime of high power and other next generation engines. A new measurement technique has been developed that uses lithium depth markers implanted in a thruster wall material. Nuclear Reaction Analysis (NRA) on the implanted material gives net erosion measurements while simultaneous Rutherford Backscattering Spectroscopy (RBS) quantifies the plasma retention and contamination in the surface layers. This insight into the surface composition and PMI is one of the major advantages of this technique when compared to other measurement methods. As an initial assessment of this technique’s applicability for plasma thrusters, it has been applied to samples of Boron Nitride exposed to the plume of a Xenon fueled BHT-200 Hall thruster and the results are presented.
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.
