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Analytical And Numerical Study Of A Hall Effect Thruster With A Particle In Cell Model
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Book Synopsis Analytical and Numerical Study of a Hall Effect Thruster with a Particle-in-cell Model by : Alejandro Benítez Martín
Download or read book Analytical and Numerical Study of a Hall Effect Thruster with a Particle-in-cell Model written by Alejandro Benítez Martín and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Space propulsion, and more specifically electric propulsion, has been growing widely strong for the last 20 years thanks to the increasingly frequent technological advances in this field. That's why there are plenty of studies arising seeking for new ways of computing simulations of propulsion systems. This is the case of the Particle-in-Cell method. This method is nowhere near new, for it started being used in the 1950s, but the computational advances in the recent years have opened new doors for this numerical method that makes it one of the best options. So, this thesis has the main purpose of proving that Particle-in-Cell simulations of a onedimensional Hall-effect thruster channel give similar results to experimental data obtained via analytical models. For it, first an introduction to different electric propulsion systems and plasma physics will be done in order to have the basis of Hall thrusters functioning so the analysis can be performed. Once the basis are settled, the analytical model will be performed comparing the results with those obtained by professor E. Ahedo and then, using the results obtained in the analytical model as reference, the numerical model using the PIC method will be computed. Finally, by discussing and comparing the two models, we will see that the results obtained in both models resemble a lot those obtained by professor E. Ahedo and the experimental data from real life thrusters, with the only difference that some discrepancies appear. In the case of the analytical model, values in electrons temperature will tend to have a sudden decrease due to not taking into account wall losses and plume divergence, while in the PIC numerical model a little oscillation appears at the beginning due to the finite difference solver used. Although the appearance of such discrepancies, the results obtained are exactly the ones that were expected, hence proving the viability of the PIC model for plasma computation.
Book Synopsis Numerical Study of Current Driven Instabilities and Anomalous Electron Transport in Hall-effect Thrusters by : Jonathan Tran
Download or read book Numerical Study of Current Driven Instabilities and Anomalous Electron Transport in Hall-effect Thrusters written by Jonathan Tran and published by . This book was released on 2017 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma turbulence and the resulting anomalous electron transport due to azimuthal current driven instabilities in Hall-effect thrusters is a promising candidate for developing predictive models for the observed anomalous transport. A theory for anomalous electron transport and current driven instabilities has been recently studied by [Lafluer et al., 2016a]. Due to the extreme cost of fully resolving the Debye length and plasma frequency, hybrid plasma simulations utilizing kinetic ions and quasi-steady state fluid electrons have long been the principle workhorse methodology for Hall-effect thruster modeling. Using a reduced dimension particle in cell simulation implemented in the Thermophysics Universal Research Framework developed by the Air Force Research Lab, we show collective electron-wave scattering due to large amplitude azimuthal fluctuations of the electric field and the plasma density. These high-frequency and short wavelength fluctuations can lead to an effective cross-field mobility many orders of magnitude larger than what is expected from classical electron-neutral momentum collisions in the low neutral density regime. We further adapt the previous study by [Lampe et al., 1971] and [Stringer, 1964] for related current driven instabilities to electric propulsion relevant mass ratios and conditions. Finally, we conduct a preliminary study of resolving this instability with a modified hybrid simulation with the hope of integration with established hybrid Hall-effect thruster simulations.
Book Synopsis Plasma Simulations by Example by : Lubos Brieda
Download or read book Plasma Simulations by Example written by Lubos Brieda and published by CRC Press. This book was released on 2019-12-13 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of plasmas is crucial in improving our understanding of the universe, and they are being increasingly utilised in key technologies such as spacecraft thrusters, plasma medicine, and fusion energy. Providing readers with an easy to follow set of examples that clearly illustrate how simulation codes are written, this book guides readers through how to develop C++ computer codes for simulating plasmas primarily with the kinetic Particle in Cell (PIC) method. This text will be invaluable to advanced undergraduates and graduate students in physics and engineering looking to learn how to put the theory to the test. Features: Provides a step-by-step introduction to plasma simulations with easy to follow examples Discusses the electrostatic and electromagnetic Particle in Cell (PIC) method on structured and unstructured meshes, magnetohydrodynamics (MHD), and Vlasov solvers Covered topics include Direct Simulation Monte Carlo (DSMC) collisions, surface interactions, axisymmetry, and parallelization strategies. Lubos Brieda has over 15 years of experience developing plasma and gas simulation codes for electric propulsion, contamination transport, and plasma-surface interactions. As part of his master’s research work, he developed a 3D ES-PIC electric propulsion plume code, Draco, which is to this date utilized by government labs and private aerospace firms to study plasma thruster plumes. His Ph.D, obtained in 2012 from George Washington University, USA, focused on a multi-scale model for Hall thrusters utilizing fluid-kinetic hybrid PIC codes. He has since then been involved in numerous projects involving development and the use of plasma simulation tools. Since 2014 he has been teaching online courses on plasma simulations through his website: particleincell.com.
Book Synopsis Parallelization of Particle-in-cell Simulation Modeling Hall-effect Thrusters by : Justin M. Fox
Download or read book Parallelization of Particle-in-cell Simulation Modeling Hall-effect Thrusters written by Justin M. Fox and published by . This book was released on 2005 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: MIT's fully kinetic particle-in-cell Hall thruster simulation is adapted for use on parallel clusters of computers. Significant computational savings are thus realized with a predicted linear speed up efficiency for certain large-scale simulations. The MIT PIC code is further enhanced and updated with the accuracy of the potential solver, in particular, investigated in detail. With parallelization complete, the simulation is used for two novel investigations. The first examines the effect of the Hall parameter profile on simulation results. It is concluded that a constant Hall parameter throughout the entire simulation region does not fully capture the correct physics. In fact, it is found empirically that a Hall parameter structure which is instead peaked in the region of the acceleration chamber obtains much better agreement with experiment. These changes are incorporated into the evolving MIT PIC simulation. The second investigation involves the simulation of a high power, central-cathode thruster currently under development. This thruster presents a unique opportunity to study the efficiency of parallelization on a large scale, high power thruster. Through use of this thruster, we also gain the ability to explicitly simulate the cathode since the thruster was designed with an axial cathode configuration.
Book Synopsis Fundamentals of Electric Propulsion by : Dan M. Goebel
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.
Book Synopsis The Effects of Insulator Wall Material on Hall Thruster Discharges: A Numerical Study by :
Download or read book The Effects of Insulator Wall Material on Hall Thruster Discharges: A Numerical Study written by and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation was undertaken to determine how the choice of insulator wall material inside a Hall thruster discharge channel might affect thruster operation. In order to study this, an evolved hybrid particle-in-cell (PIC) numerical Hall thruster model, HPHall, was used. HPHall solves a set of quasi-one-dimensional fluid equations for electrons and tracks heavy particles using a PIC method.
Book Synopsis Two Dimensional Particle-in-cell Simulation Model for Hall Type Thrusters by : Penh Koetwongjun Beidler
Download or read book Two Dimensional Particle-in-cell Simulation Model for Hall Type Thrusters written by Penh Koetwongjun Beidler and published by . This book was released on 1999 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Models of Hall Thruster Ionization Oscillations by : Ewan Samuel Kay
Download or read book Numerical Models of Hall Thruster Ionization Oscillations written by Ewan Samuel Kay and published by . This book was released on 2016 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, low frequency ionization oscillations in Hall thrusters resembling the breathing mode are studied through computational simulation. The relationship between wall erosion and discharge current oscillations is analyzed using particle-in-cell simulation, and a series of parametric simulations is used to determine the effects of macro-particle size, floating body potential, electron injection region, ion time step size, grid refinement, heavy particle mass reduction, and an artificial permittivity factor. These studies help to determine the parameters that will produce accurate simulations in the future, and identify the parts of the model that need improvement. One-dimensional steady and unsteady Hall thruster models, as well as a generalized sheath model are then developed, and the effects of the parameters that determine stability on the thruster’s operating conditions are determined.
Book Synopsis Development of the Plasma Thruster Particle-in-cell Simulator to Complement Empirical Studies of a Low-power Cusped-field Thruster by : Stephen Robert Gildea
Download or read book Development of the Plasma Thruster Particle-in-cell Simulator to Complement Empirical Studies of a Low-power Cusped-field Thruster written by Stephen Robert Gildea and published by . This book was released on 2013 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cusped-field plasma thrusters are an electric propulsion concept being investigated by several laboratories in the United States and Europe. This technology was implemented as a low-power prototype in 2007 to ascertain if durability and performance improvements over comparable Hall thruster designs could be provided by the distinct magnetic topologies inherent to these devices. The first device tested at low-powers was eventually designated the "diverging cusped- field thruster" (DCFT) and demonstrated performance capabilities similar to state-of-the-art Hall thrusters. The research presented herein is a continuation of these initial studies, geared toward identifying significant operational characteristics of the thruster using experiments and numerical simulations. After a review of hybrid, fluid, and particle-in-cell Hall thruster models, experimental contributions from this work are presented. Anode current waveform measurements provide the first evidence of the distinct time-dependent characteristics of the two main modes of DCFT operation. The previously named "high-current" mode exhibits oscillation amplitudes several factors larger than mean current values, while magnitudes in "low-current" mode are at least a full order smaller. Results from a long-duration test, exceeding 200 hours of high-current mode operation, demonstrate lifetime-limiting erosion rates about 50% lower than those observed in comparable Hall thrusters. Concurrently, the plasma thruster particle-in-cell (PTpic) simulator was developed by upgrading numerous aspects of a preexisting Hall thruster model. Improvements in performance and accuracy have been achieved through modifications of the particle moving and electrostatic potential solving algorithms. Data from simulations representing both modes of operation are presented. In both cases, despite being unable to predict the correct location of the main potential drop in the thruster chamber, the model successfully reproduces the hollow conical jet of fast ions in the near plume region. The influences guiding the formation of the simulated beam in low-current mode are described in detail. A module for predicting erosion rates on dielectric surfaces has also been incorporated into PTpic and applied to simulations of both DCFT operational modes. Two data sets from highcurrent mode simulations successfully reproduce elevated erosion profiles in each of the three magnetic ring-cusps present in the DCFT. Discrepancies between the simulated and experimental data do exist, however, and are once again attributable to the misplacement of the primary acceleration region of the thruster. Having successfully captured the most significant erosion profile features observed in high-current mode, a simulation of erosion in low-current mode indicates substantially reduced erosion in comparison to the more oscillatory mode. These findings further motivate the completion of low-current mode erosion measurements, and continued numerical studies of the DCFT. Additionally, PTpic has proven to be a useful simulation tool for this project, and has been developed with adaptability in mind to facilitate its application to a variety of thruster designs -- including Hall thrusters.
Book Synopsis Fully Kinetic Numerical Modeling of a Plasma Thruster by : James Joseph Szabo
Download or read book Fully Kinetic Numerical Modeling of a Plasma Thruster written by James Joseph Szabo and published by . This book was released on 2001 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Hall effect plasma thruster with conductive acceleration channel walls was numerically modeled using 2D3V Particle-in-Cell (PIC) and Monte-Carlo Collision (MCC) methodolo- gies. Electron, ion, and neutral dynamics were treated kinetically on the electron time scale to study transport, instabilities, and the electron energy distribution function. Axisymmet- ric R-Z coordinates were used with a non-orthogonal variable mesh to account for important small-scale plasma structures and a complex physical geometry. Electric field and sheath structures were treated self-consistently. Conductive channel walls were allowed to float electrically. The simulation included, via MCC, elastic and inelastic electron-neutral colli- sions, ion-neutral scattering and charge exchange collisions, and Coulomb collisions. The latter were also treated through a Langevin (stochastic) differential equation for the particle trajectories in velocity space. Ion-electron recombination was modeled at the boundaries, and neutrals were recycled into the flow. The cathode was modeled indirectly by inject- ing electrons at a rate which preserved quasineutrality. Anomalous diffusion was included through an equivalent scattering frequency. Free space permittivity was increased to allow a coarser grid and longer time-step. A method for changing the ion to electron mass ratio and retrieving physical results was developed and used throughout. Results were compared with theory, experiments. Gradients and anisotropy in electron temperature were observed. Non-Maxwellian electron energy distribution functions were observed. The thruster was numerically redesigned; substantial performance benefits were predicted.
Book Synopsis Dynamic Models of Electron Transport in Hall Thruster Simulations by : Eunsun Cha
Download or read book Dynamic Models of Electron Transport in Hall Thruster Simulations written by Eunsun Cha and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hall-effect thruster (HET) is an electrostatic propulsion device that relies on the Hall effect to generate a dense ExB electron current to ionize the propellant gas. In simulating Hall thrusters, describing electron cross- eld transport has been one of the greatest challenges because the electron transport in a Hall thruster is anomalously higher than that predicted by classical collision theory. Researchers have suggested some explanations of the anomalous transport, but they have failed to establish a reliable physical model for general applications. Establishing a physical model that is applicable to various types of Hall thrusters in various operating conditions is an objective of this work. In this thesis, a 2-D hybrid particle-in-cell (PIC) simulation for the Stanford Hall thruster (SHT) is used to implement the transport (electron mobility) models. Among various attempts, an entropy closure model, as well as a turbulent transport model were successfully implemented and demonstrated results that show reasonable agreement to measured data. The entropy closure model uses a 1-D entropy transport equation in the plasma of a Hall thruster discharge to derive a relation for electron mobility as a function of other plasma properties. The simulated results show a reasonable agreement with experiments. The turbulent transport model seeks for a more straightforward way to incorporate the entropy production mechanism into the simulation. By assuming that the Joule heating is the main source of entropy production, we adopted the turbulent kinetic theory to relate the energy dissipated from the largest eddies with the energy production rate. Through a scaling analysis, electron mobility is expressed as an explicit function of other plasma properties of the simulation. The simulated electron mobility captures the electron transport phenomenon measured experimentally. To test the transportability of the turbulent model, the simulation was modi ed for an SPT-type thruster with a different geometry than the SHT. Also, an alternative propellant, molecular nitrogen, was simulated on the geometry of the SHT using the turbulent model. The dynamic mobility models make it possible to observe the dynamic characteristics of the Hall thruster. The mobility models in this study magnify the capability of Hall thruster simulations to explore design space cost effectively.
Book Synopsis Hybrid Particle-in-cell Modeling and Electrostatic Probe Survey of Hall Thrusters by : John Michael Fife
Download or read book Hybrid Particle-in-cell Modeling and Electrostatic Probe Survey of Hall Thrusters written by John Michael Fife and published by . This book was released on 1998 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis International Aerospace Abstracts by :
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1998 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Particle-In-Cell Simulation of a Ceramic-lined Hall-effect Thruster by : Vincent Blateau
Download or read book Particle-In-Cell Simulation of a Ceramic-lined Hall-effect Thruster written by Vincent Blateau and published by . This book was released on 2002 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Comparison of Numerical and Experimental Near-Field Plasma Properties of the BHT-200-X3 Hall Thruster (Preprint). by :
Download or read book Comparison of Numerical and Experimental Near-Field Plasma Properties of the BHT-200-X3 Hall Thruster (Preprint). written by and published by . This book was released on 2006 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-field ion velocity distributions of a BusekBHT-200-X3 xenon Hall thruster obtained through numerical simulation are compared with laser-induced fluorescence measurements taken for one nominal operating condition. The numerical code Hybrid-PIC Hall, a 2D hybrid particle-in-cell model, is used to simulate an axisymmetric cross section of the plasma acceleration zone. A set of nine HP Hall simulations are run using three different cathode positions and Bohm electron mobility coefficients to study the effects of these parameters on ion acceleration. Six additional cases were run in an attempt to better match the simulation results to the experimental data. For model validation, agreement between the numerical and experimental results is examined. The results show that it is difficult to match both the global operational parameters (i.e, thrust, discharge current, and beam current) and the ion velocity distributions. The shape of the axial velocity distributions can be closely matched by using high Bohm electron mobility values. However, this correlation comes at the expense of peak ion velocity and discharge current agreement. Radial velocity distributions are more closely matched by the simulations, but the simulations uniformly predict lower than measured inward and higher than measured outward radial velocity components (relative to the centerline) from the annular acceleration channel.
Book Synopsis Very-Near-Field Plume Model of a Hall Thruster by : F. Taccogna
Download or read book Very-Near-Field Plume Model of a Hall Thruster written by F. Taccogna and published by . This book was released on 2003 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasmadynamic phenomena of a stationary plasma thruster (SPT-100) plume in the very-near-field region have been studied by using a two-dimensional axysimmetric numerical code based on a combination of Particle in Cell (PIC) simulation for ion component (Xe+ and Xe++) and fluid description for electrons. The model can reproduce qualitatively several experimental observations.
Book Synopsis Two-dimensional Axial-azimuthal (Z-Ø) Simulation of Cross-field Electron Transport in a Hall Thruster Plasma Discharge by : Cheryl Meilin Lam
Download or read book Two-dimensional Axial-azimuthal (Z-Ø) Simulation of Cross-field Electron Transport in a Hall Thruster Plasma Discharge written by Cheryl Meilin Lam and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hall thruster (or Hall effect thruster) is an electric propulsion device used for space flight applications. Despite its use as a deployed production technology, much of the underlying plasma physics which governs thruster behavior and performance is not well understood. Specifically, laboratory experiments indicate an anomalously high electron mobility in the direction perpendicular to the magnetic field, which exceeds that predicted by classical theory. Predicting this so-called anomalous electron transport remains a key research challenge. One possible mechanism for the generation of super-classical electron transport is the interaction of correlated quasi-coherent fluctuations in the plasma properties. Instabilities in the plasma can lead to quasi-coherent wave fluctuations in the electric potential, electron number density, and electron velocities; if these fluctuations are appropriately correlated, they can serve to either enhance or reduce electron transport across the magnetic field. In this work, we use numerical simulations as a tool to characterize axial and azimuthal fluctuations in the plasma discharge properties and study their impact on cross-field electron transport. We employ a two-dimensional axial-azimuthal (z-theta) model to simulate an annular Hall thruster discharge. We use a hybrid fluid-Particle-In-Cell approach in which the positive ion (Xe+) and neutral (Xe) species are modeled using a Particle-In-Cell (PIC) treatment and the electrons are modeled as a fluid continuum. The ion and neutral species are modeled as discrete collisionless superparticles; due to their large mass and consequently large Larmor radius, we neglect the magnetic field effect on the ions. For the electron fluid, we include the first three moments of the Boltzmann equation to obtain 2D continuity and momentum equations, using the drift-diffusion approximation, and a quasi-1D energy equation. The PIC and fluid treatments are coupled by assuming space charge neutrality, or quasineutrality, between the ions and electrons. We chose a simulated thruster model geometry and operating conditions to enable comparisons to experimental measurements of the Stanford Hall Thruster (SHT) laboratory discharge. The simulated thruster channel is 8 cm long, with an outer diameter of 9.4 cm; we include the full azimuth throughout the simulated domain, which includes the entire channel length and the near-plume. Using a non-uniform spatial resolution of 3 mm - 10 mm and maximum time step of 10 ns, we can achieve a simulated time of extent on the order of milliseconds, using a single PC processor core for a wall clock time of several days. We present results for a representative simulated low voltage operating condition. Simulated plasma properties are compared to experimental measurements of the plasma properties and the effective electron mobility. We further analyze the simulated data to characterize predicted axial and azimuthal fluctuations in the electric potential, electron number density, and electron velocities. We consider the simulated wave fluctuations in the context of linearized fluid theory models for specific dispersive propagation modes, as we attempt to characterize their impact on the effective axial electron transport for various axial regions within the thruster discharge. For the simulated time and spatial scales presented here, correlated fluctuations appear to enhance electron transport in some regions of the discharge and inhibit electron transport in others. In the mid-channel region, where we believe gradients and in the electron density and magnetic field may contribute to gradient-driven waves, we observe enhancement of the electron mobility beyond classical mobility values. Near the channel exit plane, however, we observe a distinct electron transport barrier, similar to that observed in experimental measurements. Just upstream of the channel exit plane, correlated fluctuations in the electron number density and the axial electron velocity appear to generate negative current which opposes the positive bulk discharge current; in this region, we believe the axial shear in the electron velocity may play a role in disrupting fluctuations and reducing electron transport. In both cases, it is clear that simulated wave fluctuations impact axial electron transport. Even in regions of observed transport enhancement, however, the simulated fluctuation-driven transport does not fully account for the experimentally-observed super-classical mobility. We believe that an additional transport mechanism -- perhaps electron wall scattering or higher frequency, shorter wavelength fluctuations -- is necessary to account for the experimentally-observed electron mobility. Towards this end, we present results for additional simulations which include an artificially enhanced electron collision frequency; these simulations show improved agreement with experimental results and confirm the need to include additional physical mechanisms for anomalous electron transport. Finally, suggestions for future work are included.
