DOCSLIB.ORG

Analysis of Magnetic Nozzles for Space Plasma Thrusters

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Analysis of Magnetic Nozzles for Space Plasma Thrusters Universidad Polite´cnica de Madrid Escuela Tecnica´ Superior de Ingenieros Aeronauticos´ Analysis of Magnetic Nozzles For Space Plasma Thrusters An´alisisde Toberas Magn´eticas para Motores Espaciales de Plasma Tesis Doctoral Mario Merino Mart´ınez Ingeniero Aeron´autico Madrid, junio 2013 Departamento de Fundamentos Matem´aticos de la Tecnolog´ıa Aeron´autica Escuela T´ecnica Superior de Ingenieros Aeron´auticos Analysis of Magnetic Nozzles For Space Plasma Thrusters An´alisisde Toberas Magn´eticas para Motores Espaciales de Plasma Tesis Doctoral Autor: Mario Merino Mart´ınez Ingeniero Aeron´autico Director: Eduardo Ahedo Galilea Doctor Ingeniero Aeron´autico Madrid, junio 2013 Tribunal nombrado por el Sr. Rector Magfco. de la Universidad Polit´ecnica de Madrid, el d´ıa ...... de ............... de 2013. Presidente: Francisco Jos´eHiguera Ant´on Vocal: Manuel Mart´ınez S´anchez Vocal: St´ephane Mazouffre Vocal: Davar Feili Secretario: Luis Ra´ul S´anchez Fern´andez Suplente: Juan Arturo Alonso de Pablo Suplente: Claudio Bombardelli Realizado el acto de defensa y lectura de la Tesis el d´ıa 19 de julio de 2013 en la E.T.S.I. Aeron´auticos. Calificaci´on ................................................... EL PRESIDENTE LOS VOCALES EL SECRETARIO Abstract This Thesis presents a theoretical analysis of the operation of magnetic nozzles for plasma space propulsion. The study is based on a two-dimensional, two-fluid model of the supersonic expansion of a hot plasma in a divergent magnetic field. The basic model is extended progressively to include the dominant electron convective terms, the plasma-induced magnetic field, multi-temperature electron populations, and the capability to integrate the plasma flow in the far expansion region. The hyperbolic plasma response is integrated accurately and efficiently with the method of the characteristic lines. The 2D plasma expansion is characterized parametrically in terms of the ion magnetization strength, the magnetic field geometry, and the initial plasma profile. Acceleration mechanisms are investigated, showing that the ambipolar electric field converts the internal electron energy into directed ion energy. The diamagnetic electron Hall current, which can be distributed in the plasma volume or localized in a thin current sheet at the jet edge, is shown to be central for the operation of the magnetic nozzle. The repelling magnetic force on this current is responsible for the radial confinement and axial acceleration of the plasma, and magnetic thrust is the reaction to this force on the magnetic coils of the thruster. The plasma response exhibits a gradual inward separation of the ion streamtubes from the magnetic streamtubes, which focuses the jet about the nozzle axis, gives rise to the formation of longitudinal currents and sets the plasma into rotation. The obtained thrust gain in the magnetic nozzle and radial plasma losses are evaluated as a function of the design parameters. The downstream plasma detachment from the closed magnetic field lines, re- quired for the propulsive application of the magnetic nozzle, is investigated in de- tail. Three prevailing detachment theories for magnetic nozzles, relying on plasma i ii ABSTRACT resistivity, electron inertia, and the plasma-induced magnetic field, are shown to be inadequate for the propulsive magnetic nozzle, as these mechanisms detach the plume outward, increasing its divergence, rather than focusing it as desired. Instead, plasma detachment is shown to occur essentially due to ion inertia and the gradual demagnetization that takes place downstream, which enable the unbounded inward ion separation from the magnetic lines beyond the turning point of the outermost plasma streamline under rather general conditions. The plasma fraction that remains attached to the field and turns around along the magnetic field back to the thruster is evaluated and shown to be marginal. The plasma- induced magnetic field is shown to increase the divergence of the nozzle and the resulting plasma plume in the propulsive case, and to enhance the demagnetization of the central part of the plasma jet, contrary to existing predictions. The increased demagnetization favors the earlier ion inward separation from the magnetic field. The local current ambipolarity assumption, common to many existing magnetic nozzle models, is critically discussed, showing that it is unsuitable for the study of plasma detachment. A grave mathematical inconsistency in a well-accepted model, related to the acceptance of this assumption, is found out and commented on. The formation and 2D shape of electric double layers in the plasma expan- sion is studied with the inclusion of an additional suprathermal electron popu- lation in the model. When a double layer forms, its curvature is shown to in- crease the more peripherally suprathermal electrons are injected, the lower the magnetic field strength, and the more divergent the magnetic nozzle is. The two- electron-temperature plasma is seen to have a greater magnetic-to-total thrust ratio. Notwithstanding, no propulsive advantage of the double layer is found, sup- porting and reinforcing previous critiques to their proposal as a thrust mechanism. Finally, a general framework of self-similar models of a 2D unmagnetized plasma plume expansion into vacuum is presented and discussed. The error as- sociated with the self-similarity assumption is calculated and shown to be small for hypersonic plasma plumes. Three models of the literature are recovered as particularizations from the general framework and compared. iii Resumen (Espa˜nol) Esta tesis presenta un an´alisis te´orico del funcionamiento de toberas magn´eticas para la propulsi´on espacial por plasmas. El estudio est´abasado en un modelo bi- dimensional y bi-fluido de la expansi´on supers´onica de un plasma caliente en un campo magn´etico divergente. El modelo b´asico es ampliado progresivamente con la inclusi´on de t´erminos convectivos dominantes de electrones, el campo magn´etico inducido por el plasma, poblaciones electr´onicas m´ultiples a distintas temperatu- ras, y la capacidad de integrar el flujo en la regi´on de expansi´on lejana. La respuesta hiperb´olica del plasma es integrada con alta precisi´on y eficiencia haciendo uso del m´etodo de las l´ıneas caracter´ısticas. Se realiza una caracterizaci´on param´etrica de la expansi´on 2D del plasma en t´erminos del grado de magnetizaci´on de iones, la geometr´ıa del campo magn´etico, y el perfil inicial del plasma. Se investigan los mecanismos de aceleraci´on, mostran- do que el campo ambipolar convierte la energ´ıa interna de electrones en energ´ıa dirigida de iones. Las corrientes diamagn´eticas de Hall, que pueden hallarse distri- buidas en el volumen del plasma o localizadas en una delgada capa de corriente en el borde del chorro, son esenciales para la operaci´on de la tobera, ya que la fuerza magn´etica repulsiva sobre ellas es la encargada de confinar radialmente y acelerar axialmente el plasma. El empuje magn´etico es la reacci´on a esta fuerza sobre el motor. La respuesta del plasma muestra la separaci´on gradual hacia adentro de los tubos de iones respecto de los magn´eticos, lo cual produce la formaci´on de corrien- tes el´ectricas longitudinales y pone el plasma en rotaci´on. La ganancia de empuje obtenida y las p´erdidas radiales de la pluma de plasma se eval´uan en funci´on de los par´ametros de dise˜no. Se analiza en detalle la separaci´on magn´etica del plasma aguas abajo respecto a las l´ıneas magn´eticas (cerradas sobre s´ımismas), necesaria para la aplicaci´on de la tobera magn´etica a fines propulsivos. Se demuestra que tres teor´ıas existentes sobre separaci´on, que se fundamentan en la resistividad del plasma, la inercia de electrones, y el campo magn´etico que induce el plasma, son inadecuadas para la tobera magn´etica propulsiva, ya que producen separaci´on hacia afuera en lugar de hacia adentro, aumentando la divergencia de la pluma. En su lugar, se muestra que la separaci´on del plasma tiene lugar gracias a la iv ABSTRACT inercia de iones y la desmagnetizaci´on gradual del plasma que tiene lugar aguas abajo, que permiten la separaci´on ilimitada del flujo de iones respecto a las l´ıneas de campo en condiciones muy generales. Se eval´ua la cantidad de plasma que permanece unida al campo magn´etico y retorna hacia el motor a lo largo de las l´ıneas cerradas de campo, mostrando que es marginal. Se muestra c´omo el campo magn´etico inducido por el plasma incrementa la divergencia de la tobera magn´eti- ca y por ende de la pluma de plasma en el caso propulsivo, contrariamente a las predicciones existentes. Se muestra tambi´enc´omo el inducido favorece la desmag- netizaci´on del n´ucleo del chorro, acelerando la separaci´on magn´etica. La hip´otesis de ambipolaridad de corriente local, com´un a varios modelos de tobera magn´etica existentes, es discutida cr´ıticamente, mostrando que es inade- cuada para el estudio de la separaci´on de plasma. Una inconsistencia grave en la derivaci´on matem´atica de uno de los modelos m´as aceptados es se˜nalada y comen- tada. Incluyendo una especie adicional de electrones suprat´ermicos en el modelo, se estudia la formaci´on y geometr´ıa de dobles capas el´ectricas en el interior del plasma. Cuando dicha capa se forma, su curvatura aumenta cuanto m´as perif´ericamente se inyecten los electrones suprat´ermicos, cuanto menor sea el campo magn´etico, y cuanto m´as divergente sea la tobera magn´etica. El plasma con dos temperaturas electr´onicas posee un mayor ratio de empuje magn´etico frente a total. A pesar de ello, no se encuentra ninguna ventaja propulsiva de las dobles capas, reforzando las cr´ıticas existentes frente a las propuestas de estas formaciones como un mecanismo de empuje.
Load more

Recommended publications
  • Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena
    48th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit AIAA 2012-4274 30 July - 01 August 2012, Atlanta, Georgia Magnetic Nozzle Plasma Plume: Review of Crucial Physical Phenomena Frans H. Ebersohn∗, Sharath S. Girimaji y, and David Staack z Texas A & M University, College Station, Texas 77843, USA John V. Shebalinx Astromaterials Research & Exploration Science Office, NASA Johnson Space Center, Houston, Texas 77058 Benjamin Longmier{ University of Michigan, Ann Arbor, Michigan, 48109, USA Chris Olsenk Ad Astra Rocket Company, Webster, Texas 77598 This paper presents a review of the current understanding of magnetic nozzle physics. The crucial steps necessary for thrust generation in magnetic nozzles are energy conver- sion, plasma detachment, and momentum transfer. The currently considered mechanisms by which to extract kinetic energy from the plasma include the conservation of the mag- netic moment adiabatic invariant, electric field forces, thermal energy directionalization, and Joule heating. Plasma detachment mechanisms discussed include resistive diffusion, recombination, magnetic reconnection, loss of adiabaticity, inertial forces, and self-field detachment. Momentum transfer from the plasma to the spacecraft occurs due to the interaction between the applied field currents and induced currents which are formed due to the magnetic pressure. These three physical phenomena are crucial to thrust generation and must be understood to optimize magnetic nozzle design. The operating dimension- less parameter ranges of six prominent experiments
    [Show full text]
  • Magnetic Nozzle Simulation Studies for Electric Propulsion
    Aneutronic Fusion Spacecraft Architecture 1 2 3 A. G. Tarditi , G. H. Miley and J. H. Scott 1University of Houston – Clear Lake, Houston, TX 2University of Illinois-Urbana-Champaign, Urbana, IL 3NASA Johnson Space Center, Houston, TX NIAC 2012 – Spring Meeting, Pasadena, CA Aneutronic Fusion Spacecraft Architecture 1 2 3 A. G. Tarditi , G. H. Miley and J. H. Scott 1University of Houston – Clear Lake, Houston, TX 2University of Illinois-Urbana-Champaign, Urbana, IL 3NASA Johnson Space Center, Houston, TX NIAC 2012 – Spring Meeting, Pasadena, CA Summary • Exploration of a new concept for space propulsion suitable for aneutronic fusion • Fusion energy-to-thrust direct conversion: turn fusion products kinetic energy into thrust • Fusion products beam conditioning: specific impulse and thrust compatible with needs practical mission Where all this fits: the Big Picture • “Big time” space travel needs advanced propulsion at the 100-MW level • This really means electric propulsion • Electric propulsion needs fusion Electric Space Propulsion Plasma Advanced Electric Fusion Research Propulsion Utility Technology Fusion Propulsion Introduction - Space Exploration Needs ? ? “Game changers” in the evolution of human transportation Introduction - Space Exploration Needs • Incremental modifications of existing space transportation ? designs can only go so far… • Aerospace needs new propulsion technologies Introduction - Priorities • A new propulsion paradigm that enables faster and longer distance space travel is arguably the technology development that could have the largest impact on the overall scope of the NASA mission • In comparison, every other space technology development would probably look merely incremental • Investing in R&D on new, advanced space propulsion architectures could have the largest impact on the overall scope of the NASA mission.
    [Show full text]
  • Hall2de Simulations of a Magnetic Nozzle
    AIAA Propulsion and Energy Forum 10.2514/6.2020-3642 August 24-28, 2020, VIRTUAL EVENT AIAA Propulsion and Energy 2020 Forum Hall2De Simulations of a Magnetic Nozzle Thomas A. Marks∗ University of Michigan, Ann Arbor, MI, 48109 Alejandro Lopez-Ortega † and Ioannis G. Mikellides ‡ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 Benjamin A. Jorns§ University of Michigan, Ann Arbor, MI, 48109 The two-dimensional, fluid-based Hall thruster code Hall2De is adapted to simulate a low temperature propulsive magnetic nozzle. Electron cyclotron resonance (ECR) thrusters developed at the Office National d’Etudes et de Recherches Aérospatiales (ONERA) in France and the University of Michigan are investigated. For each device, the simulated domain is defined from the nozzle throat to a location 10 thruster radii downstream. A numerical mesh is defined based on the measured magnetic field, and the governing fluid equations for singly- charge ions, electrons, and neutrals are solved. The boundary conditions for the throat of the magnetic nozzle are based on measured values of electron temperature and ion velocity. Multiple boundary conditions for the electron temperature in the downstream regions of the domain are considered. The simulated ion velocity and potential agrees well with experiment, while the simulated current densities and therefore thrusts are 50-75% higher than experiment. When a Neumann boundary condition for electron temperature is applied to the far-plume boundaries, the nozzle was seen to be purely isothermal. This suggests that the thermal conductivity along field lines in real devices is much lower than classical simulations predict, and anomalous resistivity may be needed to reproduce the temperature distribution observed in experiment.
    [Show full text]
  • Axial Momentum Gains of Ions and Electrons in Magnetic Nozzle Acceleration
    Axial momentum gains of ions and electrons in magnetic nozzle acceleration Kazuma Emoto,1,a) Kazunori Takahashi,2 and Yoshinori Takao3,b) 1Department of Mechanical Engineering, Materials Science, and Ocean Engineering, Yokohama National University, Yokohama 240-8501, Japan 2Department of Electrical Engineering, Tohoku University, Sendai 980-8579, Japan 3Division of Systems Research, Yokohama National University, Yokohama 240-8501, Japan a)E-mail: [email protected] b)E-mail: [email protected] Abstract The fully kinetic simulations of magnetic nozzle acceleration are conducted to investigate the axial momentum gains of ions and electrons with the electrostatic and Lorentz forces. Axial momentum gains per ion and electron are directly calculated from the kinetics of charged particles, indicating that electrons in the magnetic nozzle obtain the net axial momentum by the Lorentz force even though they are decelerated by the electrostatic force. Whereas ions are also accelerated by the electrostatic force, the axial momentum gain of electrons increases significantly with increasing the magnetic field strength and becomes dominant in the magnetic nozzle. In addition, it is clearly shown that the axial momentum gain of electrons is due to the electron momentum conversion from the radial to axial direction, resulting in the significant increase in the thrust and the exhaust velocity. 1 Introduction Electric propulsion systems are recognized as important devices to carry out space missions because of the advantage of the high specific impulse [1–4]. In electric propulsion systems, ion thrusters and Hall thrusters are successfully operated in space [5–7]. However, those lifetime is limited by the wear of cathodes and neutralizers since they are damaged by ion sputtering [8, 9].
    [Show full text]
  • Magnetic Nozzles for Electric Propulsion
    Magnetic nozzles for electric propulsion Mario Merino Equipo de Propulsión Espacial y Plasmas (EP2) Universidad Carlos III de Madrid (UC3M) EPIC lecture series 2017, Madrid Contents ➢ What is a magnetic nozzle (MN)? Principles of operation Plasma thrusters using MNs ➢ Acceleration and magnetic thrust generation Ambipolar electric field, electric currents, and thrust gain ➢ Plasma detachment How does the plasma separate from the closed magnetic lines? Plume divergence ➢ Conclusions Lecture notes: M. Merino, E. Ahedo, “Magnetic Nozzles for Space Plasma Thrusters” Encyclopedia of Plasma Technology, 2016. Downloadable at: http://mariomerino.uc3m.es Magnetic nozzles for electric propulsion Mario Merino 2 What is a magnetic nozzle? ➢ A magnetic nozzle (MN) is a convergent-divergent magnetic field created by coils or permanent magnets to guide the expansion of a hot plasma, accelerating it supersonically and generating thrust ➢ The MN works in a similar way to a traditional “de Laval” nozzle with a neutral gas, except that: The nozzle walls (and its reaction force on the expanding gas) are substituted by magnetic lines (and a magnetic force on the charged particles that compose the plasma) solenoids Supersonic Hot plasma plasma expansion Magnetic tubes AF-MPD (IRS) RL-10 rocket “de Laval” nozzle A magnetic nozzle in operation Magnetic nozzles for electric propulsion Mario Merino 3 What is a magnetic nozzle? ➢ The MN has the following advantages: It operates contactlessly: we avoid touching the hot plasma ❖ No erosion of the walls, no heat
    [Show full text]
  • Magnetic Nozzle Design for High-Power MPD Thrusters
    Magnetic Nozzle Design for High-Power MPD Thrusters IEPC-2005-230 Presented at the 29th International Electric Propulsion Conference, Princeton University, October 31 – November 4, 2005 Robert P. Hoyt* Tethers Unlimited, Inc., Bothell, WA, 98011, USA Abstract: Magnetoplasmadynamic (MPD) thrusters can provide the high-specific impulse, high-power propulsion required to enable ambitious Human and Robotic Exploration missions to the Moon, Mars, and outer planets. MPD thrusters, however, have traditionally been plagued by poor thrust efficiencies. In most operating modes, these inefficiencies are caused primarily by deposition of power into the anode due to the anode fall voltage. Prior investigations have indicated that the Hall Effect term in Ohm’s law causes depletion of the plasma near the anode surface, which in turn results in the anode fall and onset behavior contributing to rapid electrode erosion. Under a NASA/GRC Phase I SBIR Phase I effort, we have used analytical methods and the MACH2 code to first investigate the impacts of the Hall term on the behavior of MPD thrusters and then to evaluate several magnetic nozzle concepts for their ability to counter the Hall-induced starvation effects. Through a process of iteration between custom magnetic field design tools and the plasma simulations, developed new magnetic nozzle designs for both the GRC Benchmark MPD thruster. We then designed and fabricated a prototype suitable for testing on the GRC Benchmark thruster in a vacuum chamber facility. If these magnetic nozzles prove successful in minimizing anode fall losses, they could result in dramatic improvements in the thrust efficiency of MPD devices. I.
    [Show full text]
  • Magnetic Field Effects on Plasma Plumes
    39th EPS Conference & 16th Int. Congress on Plasma Physics O2.404 Magnetic Field Effects on Plasma Plumes F. Ebersohn1,2, J. Shebalin1, S. Girimaji2, D. Staack2 1 NASA, Johnson Space Center, Houston, USA 2 Texas A&M University, College Station, TX, USA Space plasma propulsion systems currently being developed require strong guiding magnetic fields known as magnetic nozzles to control plasma flow and produce thrust. Among these propulsion methods are the VAriable Specifc Impulse Magnetoplasma Rocket (VASIMR)[1], magnetoplasmadynamic thrusters (MPDs), and helicon thrusters. Magnetic nozzles are func- tionally similar to de Laval nozzles, but are inherently more complex systems due to the plas- madynamics resulting from the magnetic field effects on the plasma plume. Here, we perform a preliminary study of numerical magnetic nozzle experiments. The crucial physical phenomenon of magnetic nozzles are thrust production and plasma de- tachment. The physics of thrust production encompasses conversion of magnetoplasma energy into directed kinetic energy as well as the mechanisms for transferring momentum to the space- craft. The physics of plasma detachment governs the separation of plasma from the spacecraft and must be understood to optimize nozzle design for maximum efficiency. The mechanisms for inducing efficient detachment are an active research topic. The goal of this research is to perform numerical experiments in the magnetohydrodynamic (MHD) regime observing which physical phenomena occur and optimizing magnetic nozzle design accordingly. To perform numerical experiments a novel, hybrid kinetic theory and single fluid MHD solver known as the Magneto-Gas Kinetic Method (MGKM) was developed[2]. The solver is com- prised of a "fluid" portion that finds solutions to the Navier Stokes equations through the Gas Ki- netic Method (GKM)[3] and "magnetic" portion that incorporates MHD physics through source terms to the conserved fluid variables.
    [Show full text]
  • Magnetic Nozzle Efficiency in a Low Power Inductive Plasma Source
    Plasma Sources Science and Technology PAPER Magnetic nozzle efficiency in a low power inductive plasma source To cite this article: T A Collard and B A Jorns 2019 Plasma Sources Sci. Technol. 28 105019 View the article online for updates and enhancements. This content was downloaded from IP address 141.213.172.164 on 31/10/2019 at 17:55 Plasma Sources Science and Technology Plasma Sources Sci. Technol. 28 (2019) 105019 (18pp) https://doi.org/10.1088/1361-6595/ab2d7d Magnetic nozzle efficiency in a low power inductive plasma source T A Collard and B A Jorns University of Michigan, Ann Arbor, MI 48109, United States of America E-mail: [email protected] Received 23 February 2019, revised 4 June 2019 Accepted for publication 27 June 2019 Published 29 October 2019 Abstract The nozzle efficiency and performance of a magnetic nozzle operating at low power (<200 W) are experimentally and analytically characterized. A suite of diagnostics including Langmuir probes, emissive probes, Faraday probes, and laser induced fluorescence are employed to map the spatial distribution of the plasma properties in the near-field of a nozzle operated with xenon and peak magnetic field strengths ranging from 100 to 600 G. The nozzle efficiency is found to be <10% with plasma thrust contributions <120 μN and specific impulse <35 s. These performance measurements are compared with predictions from quasi-1D idealized nozzle theory and found to be 50%–70% of the model predictions. It is shown that the reason for this discrepancy stems from the fact that the underlying assumption of the idealized model—that ions are sonic at the throat of the nozzle—is violated at low power operation.
    [Show full text]
  • Fully Magnetized Plasma Flow in a Magnetic Nozzle Mario Merino and Eduardo Ahedo
    Fully magnetized plasma flow in a magnetic nozzle Mario Merino and Eduardo Ahedo Citation: Physics of Plasmas 23, 023506 (2016); doi: 10.1063/1.4941975 View online: http://dx.doi.org/10.1063/1.4941975 View Table of Contents: http://scitation.aip.org/content/aip/journal/pop/23/2?ver=pdfcov Published by the AIP Publishing Articles you may be interested in A magnetic nozzle calculation of the force on a plasma Phys. Plasmas 19, 033507 (2012); 10.1063/1.3691650 On plasma detachment in propulsive magnetic nozzles Phys. Plasmas 18, 053504 (2011); 10.1063/1.3589268 Status of Magnetic Nozzle and Plasma Detachment Experiment AIP Conf. Proc. 813, 465 (2006); 10.1063/1.2169224 Magnetohydrodynamic scenario of plasma detachment in a magnetic nozzle Phys. Plasmas 12, 043504 (2005); 10.1063/1.1875632 Magnetic‐Laval‐Nozzle Effect on a Magneto‐Plasma‐Dynamic Arcjet AIP Conf. Proc. 669, 306 (2003); 10.1063/1.1593926 Reuse of AIP Publishing content is subject to the terms at: https://publishing.aip.org/authors/rights-and-permissions. Downloaded to IP: 163.117.179.242 On: Thu, 18 Feb 2016 17:44:42 PHYSICS OF PLASMAS 23, 023506 (2016) Fully magnetized plasma flow in a magnetic nozzle Mario Merinoa) and Eduardo Ahedob) Equipo de Propulsion Espacial y Plasmas (EP2), Universidad Carlos III de Madrid, Leganes, Spain (Received 8 December 2015; accepted 2 February 2016; published online 18 February 2016) A model of the expansion of a plasma in a magnetic nozzle in the full magnetization limit is presented. The fully magnetized and the unmagnetized-ions limits are compared, recovering the whole range of variability in plasma properties, thrust, and plume efficiency, and revealing the differences in the physics of the two cases.
    [Show full text]
  • Future Directions for Electric Propulsion Research
    aerospace Article Future Directions for Electric Propulsion Research Ethan Dale * , Benjamin Jorns and Alec Gallimore Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48105, USA; [email protected] (B.J.); [email protected] (A.G.) * Correspondence: [email protected] Received: 7 July 2020; Accepted: 17 August 2020; Published: 20 August 2020 Abstract: The research challenges for electric propulsion technologies are examined in the context of s-curve development cycles. It is shown that the need for research is driven both by the application as well as relative maturity of the technology. For flight qualified systems such as moderately-powered Hall thrusters and gridded ion thrusters, there are open questions related to testing fidelity and predictive modeling. For less developed technologies like large-scale electrospray arrays and pulsed inductive thrusters, the challenges include scalability and realizing theoretical performance. Strategies are discussed to address the challenges of both mature and developed technologies. With the aid of targeted numerical and experimental facility effects studies, the application of data-driven analyses, and the development of advanced power systems, many of these hurdles can be overcome in the near future. Keywords: electric propulsion; Hall effect thruster; gridded ion thruster; electrospray; magnetic nozzle; pulsed inductive thruster 1. Introduction The use of electric propulsion (EP) for space applications is currently undergoing a rapid expansion. There are hundreds of operational spacecraft employing EP technologies with industry projections showing that nearly half of all commercial launches in the next decade will have a form of electric propulsion. In light of their widespread use, the thruster types that have fueled this expansion—moderately-powered (1–20 kW) Hall effect, electrothermal, and ion thrusters—arguably have now achieved “mature” operational status.
    [Show full text]
  • Magnetic Nozzle Plasma Thruster ~ Helicon and Helicon MPD Thruster ~
    プラズマ若手研究会＠原研 (2015.3.3) Magnetic nozzle plasma thruster ~ Helicon and Helicon MPD thruster ~ Department of Electric Engineering, Tohoku University Kazunori Takahashi Collaborators: Prof Christine Charles and Prof Rod Boswell (Australian National University) Dr Trevor Lafleur (Ecopolytechnique) Prof Amnon Fruchtman (Holon Institute of Technology) Prof Michael A Lieberman (UC Berkeley) Prof Tamiya Fujiwara and Prof Koichi Takaki (Iwate University) Prof Akira Ando Students in Iwate and Tohoku Universities Here I would like to briefly review the results on the magnetic nozzle plasma thruster in Iwate University (2007- 2012), in the Australian National University (sabbatical year 2010-2011), and in Tohoku University (2013-). 電気推進機 (プラズマ推進機) 化学推進機 化学燃料を燃焼し一気に噴射する 特徴：莫大な推進力 (数千 kN)． ソーラーパネル 燃料使用量が多い． 電力 プラズマ生成・加速 僅かな燃料 等 をプラズマ化 プラズマ流噴射 (Xe, Ar ) 燃料ガス し，イオンを電気的な力で加速する ことで，超高速で噴射 特徴：小さい推進力 (mN – 1 N)． 燃料使用量が少ない． はやぶさ (JAXA) 推力 推力 = 推進機から放出した運動量 Conventional electric propulsion Electromagnetic acceleration Electrostatic acceleration MPD arcjet thruster Hall effect thruster Ion gridded thruster Magnetic nozzle The magnetic nozzle seems to arise various types of plasma acceleration and momentum conversion mechanisms. This work is aimed to fully understand the magnetic nozzle physics in the wide range of the parameters and develop a high performance plasma thruster. The biggest problem called PLASMA DETACHMENT still remains future issue (we might need a big big big tank or space test.) Thruster facilities in Sendai HPT-I HITOP HPT-XS TMP rf matching box Diffusion chamber Helicon MPD 60-cm-diam and 140-cm-length tank 70-cm-diam and 400-cm-length tank 14-cm-diam and ~50-cm-length tank 500 l/s pumping speed 1500 l/s pumping speed 300 l/s pumping speed Prf < 2 kW High power MPD power supply Prf < 2 kW Electrodeless helicon thruster Lab test of MPD thruster MPD power supply (~ 100 J) Individual measurement of thrust components Lab test of helicon MPD thruster Mega-HPT PMPI (In Iwate) P < 10 kW 100-cm-diam and 200-cm-length tank rf 5000 l/s pumping speed.
    [Show full text]
  • Plasma Technologies for Aerospace Applications
    Plasma Technologies for Aerospace Applications Alfonso G. Tarditi Engineering and Science Contract Group NASA Johnson Space Center and University of Houston, Clear Lake Outline • Plasmas • Main Thrust for Plasma Research: Fusion Energy • Aerospace Applications • Research at UHCL Plasmas The “Fourth State” of the Matter • The matter in “ordinary” conditions presents itself in three fundamental states of aggregation: solid, liquid and gas. • These different states are characterized by different levels of bonding among the molecules. • In general, by increasing the temperature (=average molecular kinetic energy) a phase transition occurs, from solid, to liquid, to gas. • A further increase of temperature increases the collisional rate and then the degree of ionization of the gas. The “Fourth State” of the Matter (II) • The ionized gas could then become a plasma if the proper conditions for density, temperature and characteristic length are met (quasineutrality, collective behavior). • The plasma state does not exhibit a different state of aggregation but it is characterized by a different behavior when subjected to electromagnetic fields. The “Fourth State” of the Matter (III) Plasmas (V) Debye Shielding • An ionized gas has a certain amount of free charges that can move in presence of electric forces Debye Shielding (II) • Shielding effect: the free charges move towards a perturbing charge to produce, at a large enough distance lD, (almost) a neutralization of the electric field. lD E E~0 Debye Shielding (IV) • The quantity 0kTB lDe 2 nqe
    [Show full text]