Download or read book A Collisional Radiative Model for Xe Electrical Thrusters written by G. Colonna and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Near Infrared Collisional Radiative Model for Xe Plasma Electrostatic Thrusters The Role of Metastable Atoms written by and published by . This book was released on 2009 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metastable Xe atoms play an important role in the collisional radiative processes of dense xenon plasmas, including those of electric thrusters for space vehicles. Recent measurements and calculations of electron-excitation processes out of the metastable state have allowed for the development of a collisional radiative model for Xe near-infrared (NIR) emissions based on the population of the metastable level through radiative transitions, and based on depopulation through electron-impact excitation. A modified plasma radiative model incorporating newly computed electron-impact excitation cross sections using both relativistic distorted wave and semi-relativistic Breit-Pauli B-Spline R-matrix methods is presented. The model applies to optically thin, low-density regions of the thruster plasma and is most accurate at electron temperatures below 10 eV. The model is tested on laboratory spectral measurements of the D55 TAL and BHT-200 Hall thruster plasma NIR radiation. The metastable neutral fraction is determined to rise from 0.1 to slightly above. The electron temperature increases from ~2 to 10 eV, reaching a maximum around 15 eV. Electron temperatures derived with the modified model are approximately 20% lower than a previous version of the model that used an approximate approach to account for metastable population and line intensity enhancement.

Download or read book Passive Optical Diagnostic of Xe Propelled Hall Thrusters II Collisional Radiative Model written by and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collisional radiative model is presented for analyzing the xenon-propelled Hall Thruster optical radiation based on apparent electron and ion-impact emission cross sections associated with lines in the visible and near-infrared region of the spectrum. The emission cross sections of selected near-infrared emission lines are incorporated in a collisional-radiative model. The effect of Stepwise excitation via metastable states on the derived line intensities for emissions from XeI 5p56p(6p') levels is evaluated. Meanwhile, visible XeII emissions are shown to provide plasma densities at high electron temperature conditions. The electron temperature and spatial ion number density distribution were determined from the luminescence spectra measured in the discharge and plume near-field plasma of the Hall thruster, the TSNIIMASH D-55 anode layer-thruster. The results are in good. agreement with the probe measurement data and simulations reported in the literature for the same thruster. The analysis of the Hall thruster XeI near-infrared spectra demonstrates that the neglect of ion-atom collisions results in an erroneous electron temperature determination at electron temperatures below 10 eV.

Download or read book Ion Collision Emission Excitation Cross Sections for Xenon Electric Thruster Plasmas written by and published by . This book was released on 2008 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energetic xenon ion collisions with neutral atoms play an important role in electric thruster plasma radiation at low electron temperatures. The respective emission excitation cross sections are necessary for the derivation of plasma parameters from the observed radiance. We present apparent emission excitation cross sections for near-infrared 5p(exp 5)6p to 5p(exp 5)6s transitions of neutral xenon impacted by singly and doubly charged xenon ions. The cross sections were measured over a laboratory energy-per-charge-number range of 100 to 900 eV, a range that covers typical Hall effect thruster discharge voltages. The cross sections are derived from ion beam luminescence spectra produced at single-collision conditions and at pressures for which radiation trapping effects were shown to be negligible. The Xe(exp 2+) cross sections are significantly higher than those of Xe2+ and increase with energy throughout the investigated range. The Xe(exp 2+) cross sections plateau at approximately 600 eV. The cross sections are incorporated in a collisional-radiative model. The calculations of near-infrared spectra demonstrate that the sensitivity of the model diagnostic with respect to electron temperature increases with ion energy.

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 Experimental and Computational Studies of Electric Thruster Plasma Radiation Emission written by Murat Alp Çelik and published by . This book was released on 2007 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electric thrusters are being developed for in-space propulsion needs of spacecraft as their higher specific impulse enables a significant reduction in the required propellant mass and allows longer duration missions. Over the last few decades many different electric propulsion concepts have been proposed and studied. In studying the electric thrusters, in order to improve the thruster performance as well as to understand the underlying physics of thruster's operation, various diagnostics methods were employed. As one unique method, emission spectroscopy provides a non-invasive, fast and economical diagnostic allowing also the ability to access hard to reach locations. In this study, emission spectroscopy is employed as a means to determine the trends in thruster operations as well as diagnosing the plasma parameters. This study presents the spectral measurement results of three different electric thrusters and plasma sources. First, the BHT-200 Hall thruster emission spectra measurements are presented for varying discharge voltage and for various regions of observation.

Download or read book 04 2370 04 2473 written by and published by . This book was released on 2004 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Journal of Propulsion and Power written by and published by . This book was released on 2008 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radiation from Pulsed Electric Thrusters written by Keith I. Thomassen and published by . This book was released on 1973 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theoretical models for the radiation from pulsed electric thrusters are given and predicted intensities and spectra are compared with measurements made on a particular thruster of this type. From this comparison the source of radiation is identified and the potential for interference with on-board satellite communications systems is estimated. (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Excitation of Atoms and Broadening of Spectral Lines written by Igor I. Sobel'man and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: A survey of elementary processes and mechanisms, presenting useful and relatively simple methods of approximation for calculating the effective cross sections, giving a number of approximate formulas. Extensive tables list cross sections and rate coefficients for various atoms and elementary processes. For this second edition several sections and formulas have been substantially revised, the tables recalculated using the updated version of ATOM and recent progress in the field has been added.

Download or read book Plasma Polarization Spectroscopy written by Takashi Fujimoto and published by Springer. This book was released on 2010-10-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: You’ll learn all the underlying science and how to perform all the latest analytical techniques that plasma polarization spectroscopy (PPS) offers with this new book. The authors report on recent results of laboratory experiments, keeping you current with all the latest developments and applications in the field. There is also a timely discussion centered on instrumentation that is crucial to your ability to perform successful PPS experiments.

Download or read book Numerical Simulations of the Plumes of Electric Propulsion Thrusters written by Douglas Bryan VanGilder and published by . This book was released on 2000 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electric Thruster Research written by and published by . This book was released on 1982 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Field Emission Electric Propulsion Thruster Modeling and Simulation written by Anton Sivaram VanderWyst and published by . This book was released on 2006 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: Both asymptotic analysis and numerical simulations, based on a new approach combining level set and boundary element methods, were used to simulate 2D-planar and 2D-axisymmetric probability density functions of the droplets produced for a given geometry and electrode potential. The combined algorithm allows the simulation of electrostatically-driven liquids up to and after detachment. Second order accuracy in space is achieved using a volume of fluid correction.

Download or read book Flexible Three Dimensional Modeling of Electric Thrusters in Vacuum Chambers written by and published by . This book was released on 2003 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: A national team of researchers is developing a software system, COLISEUM, which performs calculations of plasma propagation and interaction with arbitrary 3%D surfaces. The applications of COLISEUM are wide- ranging, hut include simulating engine test configurations inside vacuum chambers and predicting sputtering and re-deposition on spacecraft surfaces. COLISEUM allows users to easily define complicated 3-D geometries using off the shelf CAD software, then select from a set of plasma expansion models of varying fidelities and numerical complexity to perform the solution. Once the object surfaces are created, the user can run different types of simulations for the same geometry. With this system, low fidelity models can he used to verify the geometry and boundary conditions, and to obtain first-order predictions. Higher fidelity models are then used to obtain more accurate predictions with greater cost in computation time. This paper describes the simulation of a Hall thruster firing inside a vacuum chamber, and the execution of two types of simulations for the same geometry: one in which the equilibrium sputter and deposition rates are calculated, and another in which the Hall thruster plume expansion is calculated. The sputter and deposition calculations are made with an iterative ray tracing algorithm which takes into account re-sputtering of deposited material. The plume expansion calculations are performed with a particle-in-cell (PIC) algorithm which includes wall collisions and wall recombination. Techniques are incorporated that decrease the computation time required for the PIC simulation to relax to steady state.

Download or read book Aerospace America written by and published by . This book was released on 2000 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt: