Analysis of Streamer Propagation in Atmospheric Air Manfred Heiszler Iowa State University
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Study of Memory Effect in an Atmospheric Pressure Townsend
THÈSE En vue de l’obtention du DOCTORAT DE L’UNIVERSITÉ DE TOULOUSE Délivré par l'Université Toulouse 3 - Paul Sabatier Présentée et soutenue par Xi LIN Le 22 février 2019 Study of memory effect in an Atmospheric Pressure Townsend Discharge in the mixture N2/O2 using laser induced fluorescence Ecole doctorale : GEET - Génie Electrique Electronique et Télécommunications : du système au nanosystème Spécialité : Ingénierie des Plasmas Unité de recherche : LAPLACE - Laboratoire PLAsma et Conversion d'Énergie - CNRS-UPS-INPT Thèse dirigée par Simon DAP et Nicolas GHERARDI Jury Mme Svetlana Starikovskaia, Rapporteuse M. Ronny Brandenburg, Rapporteur Mme Françoise Massines, Examinateur M. Frédéric Marchal, Examinateur M. Philippe Teulet, Examinateur M. Simon DAP, Directeur de thèse Acknowledgement I would like to express my deepest thanks to my supervisor, Simon Dap. He has devoted so much time on teaching and leading me into the world of plasma physics. I am very appreciated for his patience and encouragement, also thanks to his support and rich discussion on physics, I finally achieve my thesis. I would also like to express my thanks to Nicolas Naudé for the fruitful discussions and suggestions on electrical characteristics of discharge, and for his knowledge on electrode fabrication and on OES spectroscopy. Thanks to Nicolas Gherardi for his confidence and support on me. Thanks to Prof. Svetlana M Starikovskaia and Prof. Ronny Brandenburg, for reviewing my thesis. I would also like to extend my gratitude to three other jury members, Prof. Françoise Massines, Prof. Feédéric Marchal and Prof. Philippe Teulet, for being the examiners of my work. I appreciate the assistance and advice from the technicians and engineers of Laplace, Benoît Schlegel, Fédéric Sidor, Vincent Bley, Céline Combettes, Cédric Trupin, and Stéphane Martin. -
An Introduction to Quantum Field Theory
AN INTRODUCTION TO QUANTUM FIELD THEORY By Dr M Dasgupta University of Manchester Lecture presented at the School for Experimental High Energy Physics Students Somerville College, Oxford, September 2009 - 1 - - 2 - Contents 0 Prologue....................................................................................................... 5 1 Introduction ................................................................................................ 6 1.1 Lagrangian formalism in classical mechanics......................................... 6 1.2 Quantum mechanics................................................................................... 8 1.3 The Schrödinger picture........................................................................... 10 1.4 The Heisenberg picture............................................................................ 11 1.5 The quantum mechanical harmonic oscillator ..................................... 12 Problems .............................................................................................................. 13 2 Classical Field Theory............................................................................. 14 2.1 From N-point mechanics to field theory ............................................... 14 2.2 Relativistic field theory ............................................................................ 15 2.3 Action for a scalar field ............................................................................ 15 2.4 Plane wave solution to the Klein-Gordon equation ........................... -
Chapter 3 Beam Dynamics II - Longitudinal
Chapter 3 Beam Dynamics II - Longitudinal Sequences of Gaps Transit Time Factor Phase Stability Chapter 3 Longitudinal Beam Dynamics 1 The Faraday Cage Protons are confined in a conducting box, at low energy. Assume they can bounce off the walls with no energy loss. Move the switch from position A to B. The potential on the box rises from 0 to 1 MV. What is the proton energy now? Chapter 3 Longitudinal Beam Dynamics 2 The Linac Drift Tube A linear accelerator (linac) is comprised of a succession of drift tubes. These drift tubes have holes in their ends so the particles can enter and exit, and when particles are inside the drift tube, a Faraday Cage, the potential of the drift tube may vary without changing the energy of the particle. Acceleration takes place when a charged particle is subjected to a field. The field inside the Faraday cage is not affected by the potential outside. (Aside from fields generated by the protons themselves, the field inside the Faraday cage is zero.) The drift tubes are arranged in a sequence with a passage through their middle for the particles to pass. The field in the gap between the drift tubes accelerates the particles. Chapter 3 Longitudinal Beam Dynamics 3 Some Actual Linac Configurations We will look at: Sloan-Lawrence Structure (Ising, Wideroe) Alvarez Structure RFQ Structure Coupled-Cavity Structure Chapter 3 Longitudinal Beam Dynamics 4 Some Kinematics For simplicity, we will assume the particles are non-relativistic. The normalized velocity is 2T = m c2 T is the kinetic energy of the particle, mc2 is the rest mass, 938 MeV for protons. -
Experiments and Simulations of an Atmospheric Pressure Lossy Dielectric Barrier Townsend Discharge
Journal of Physics D: Applied Physics PAPER Related content - Atmospheric pressure glow discharge Experiments and simulations of an atmospheric plasma A A Garamoon and D M El-zeer pressure lossy dielectric barrier Townsend - Diffuse barrier discharges discharge Z Navrátil, R Brandenburg, D Trunec et al. - Nonlinear phenomena in dielectric barrier discharges: pattern, striation and chaos To cite this article: S Im et al 2014 J. Phys. D: Appl. Phys. 47 085202 Jiting OUYANG, Ben LI, Feng HE et al. Recent citations View the article online for updates and enhancements. - Radial structures of atmospheric-pressure glow discharges with multiple current pulses in helium Zhanguo Bai et al This content was downloaded from IP address 128.12.245.233 on 22/09/2020 at 18:06 Journal of Physics D: Applied Physics J. Phys. D: Appl. Phys. 47 (2014) 085202 (10pp) doi:10.1088/0022-3727/47/8/085202 Experiments and simulations of an atmospheric pressure lossy dielectric barrier Townsend discharge S Im, M S Bak1, N Hwang2 and M A Cappelli Mechanical Engineering Department, Stanford University, Stanford, California 94305-3032, USA E-mail: [email protected] Received 25 September 2013, revised 7 January 2014 Accepted for publication 9 January 2014 Published 7 February 2014 Abstract A diffuse discharge is produced in atmospheric pressure air between porous alumina dielectric barriers using low-frequency (60 Hz) alternating current. To study its formation mechanism, both the discharge current and voltage are measured while varying the dielectric barrier porosity (0%, 48% or 85%) and composition (99% Al2O3 ,99% SiO2 or 75% Al2O3 + 16% SiO2 + 9% other oxides). -
Background Information Lichtenberg Figures
Factors That Affect Lichtenberg Figures Name Institution Date Background information Lichtenberg Figures Lichtenberg Figures are caused by electric discharges that sometimes occur on the surface of or inside insulating materials, such as wood, acrylic, or even human skin. German Physicist Georg Christoph Lichtenberg discovered them and subsequently researched them. In 1777, Lichtenberg built a large electrophorus to generate high voltage static electricity, after then discharging this high voltage he used pressed paper to record these patterns, this discovering the basic principle of xerography (What are Lichtenberg Figures? A bit of history..., 2020). These figures are of enormous interest because they exhibit fractal properties. A fractal is a never-ending pattern which repeats itself at different scales. This property is called “Self-Similarity”. Fractals are very complex; however, they are made by a straightforward repeating process. Fractals appear a lot in nature, such as in the shape of galaxies, hurricanes, and trees. One Fractal which is particularly well known is the Mandelbrot Set. What gives rise to these structures in nature? In this essay, I hypothesize what factors affect the formation of these Lichtenberg figures in insulating materials. Main Body The hypothesis I will discuss is that the following points affect the geometry Lichtenberg Figure; Distance between contact points, Duration of exposure, and Variation of material. As Lichtenberg Figures are caused by dielectric breakd changing these properties alter the electrodynamic properties of the material. By their very nature insulators do not readily allow current to flow through them, however the case of dialectic breakdown, we can see that this must be occurring. -
Lichtenberg Figures and How Are They Produced? Copyright Stoneridge Engineering, 1999-2004, Updated 8/15/04
What are Lichtenberg Figures and how are they produced? Copyright Stoneridge Engineering, 1999-2004, Updated 8/15/04 Lichtenberg Figures are patterns that are formed on the surface or inside insulating materials by high voltage electrical discharges. The first Lichtenberg Figures were actually two-dimensional patterns formed in dust on a charged plate in the laboratory of their discoverer, Georg Christoph Lichtenberg (1742-1799), a German physicist. The basic principles involved in the formation of these early figures are also fundamental to the operation of modern copy machines and laser printers. Using modern materials and powerful particle accelerators, 3-D Lichtenberg Figures can now be created inside clear plastic blocks, permanently forming beautiful “Captured Lightning ™”. Acrylic plastic (Polymethylmethacrylate - PMMA) is used as the medium for our Lichtenberg Figures because it has an excellent combination of optical, dielectric, and mechanical properties. A linear accelerator (LINAC) is used to produce large numbers of high-speed electrons - a high-energy electron beam (e-beam). Electrons in the beam are accelerated to up to 99.5% of the speed of light. These “relativistic” electrons have acquired a very large amount of kinetic energy (measured in Millions of Electron Volts or MeV). Specially selected and prepared pieces of acrylic are placed in the path of this electron beam. As the energetic electrons in the beam hit the surface of the acrylic, they don’t immediately stop. Instead, they collide with the molecules of acrylic, slowing down and coming to rest deep inside the block. Under continued irradiation, electrons rapidly accumulate inside the acrylic, forming a layer of excess negative charge called a space charge. -
Electrostatic Discharges and Multifractal Analysis of Their Lichtenberg figures
J. Phys. D: Appl. Phys. 32 (1999) 219–226. Printed in the UK PII: S0022-3727(99)96851-1 Electrostatic discharges and multifractal analysis of their Lichtenberg figures T Ficker Department of Physics, Technical University, Ziˇ zkovaˇ 17, CZ-602 00 Brno, Czech Republic Received 17 August 1998, in final form 30 September 1998 Abstract. Morphological features of Lichtenberg figures created by electrostatic separation discharges on the surfaces of electret samples have been studied by means of multifractal analysis. The monofractal ramification of surface positive-channel streamers has been confirmed and found to be dependent on actual experimental conditions. For the lower level of electret saturation used, the fractal dimension D 1.4 of the surface Lichtenberg channels has been obtained. Various registration features of electret≈ and non-electret samples have been discussed and illustrated. 1. Introduction The majority of the studies dealing with Lichtenberg figures has used point-to-plane electrode systems and short Typical electrostatic discharges arise during separation of a voltage pulses in the microsecond and nanosecond regimes. charged sheet of a highly resistive material from a grounded The consequence of such special experimental arrangements object. Such electrostatic discharges are sometimes called is the characteristic form of the corresponding Lichtenberg ‘separation discharges’. Their damaging effects on some figures: a single circular star-shaped channel structure for a industrial products are well known: they degrade tracks on positive pulse (positive streamers) and a single circular spot paper and photographic materials, induce noise in electronic built up in a practically continuous manner for a negative components or cause inconvenience for the human body, pulse (negative streamers). -
Injuries and Deaths from Lightning J Clin Pathol: First Published As 10.1136/Jclinpath-2020-206492 on 12 August 2020
Review Injuries and deaths from lightning J Clin Pathol: first published as 10.1136/jclinpath-2020-206492 on 12 August 2020. Downloaded from Ryan Blumenthal Department of Forensic ABSTRACT above zero at the base of the cloud to aboutminus Medicine, University of Pretoria, This paper reviews recent academic research into 50°C at its top. Violent up and down draughts and Pretoria, Gauteng, South Africa the pathology of trauma of lightning. Lightning may severe turbulence occur in specific regions of the injure or kill in a variety of different ways. Aimed at the cloud.8 Correspondence to Professor Ryan Blumenthal, trainee, or practicing pathologist, this paper provides a According to Malan (1967), an electrically active Department of Forensic clinicopathological approach. thundercloud may be regarded as an electrostatic Medicine, University of Pretoria, generator suspended in an atmosphere of low Private Bag X323, Gezina, 0031, electrical conductivity. It is situated between two South Africa; ryan. blumenthal@ As Ponocrates grew familiar with Gargantua’s vi- up. ac. za cious manner of studying, he began to plan a differ- concentric conductors, namely, the surface of the ent course of education for the lad; but at first he let earth and the electrosphere, the latter being the Received 27 March 2020 him go on as before knowing that nature does not highly conducting layers of the atmosphere at alti- Revised 30 June 2020 9 endure abrupt changes without great violence. tudes above 50–60 km. Accepted 3 July 2020 Published Online First Rabelais, “The Old Education and the New”, Gar- There are different types of lightning discharges: 12 August 2020 gantua, Book 1. -
Relativistic Runaway Electrons Above Thunderstorms
Relativistic Runaway Electrons above Thunderstorms Nikolai G. Lehtinen Physics Department STAR Laboratory Stanford University Advisers: Umran S. Inan, EE Department, Timothy F. Bell, EE Department, Roger W. Romani, Physics Department Plan 1. Introduction 2. Monte Carlo model of runaway electron avalanche 3. Fluid model of runaway electrons above thunderstorms 4. Effects of runaway electrons in the conjugate hemisphere Lightning-mesosphere interaction phenomena ~ 2000 cm-3 Electron density Β 100 km THERMOSPHERE Elves 80 km Sprites MESOSPHERE γ-rays 60 km Runaway ~100 MV 40 km E ~ 103 V/m electrons STRATOSPHERE at 40 km Blue Jet 20 km Cameras + + + + + TROPOSPHERE +CG 0 km - --- - γ-ray flash Red Sprites (BATSE observation) 40 Elves 30 20 Sprites 10 Rate (counts/0.1ms) 0 015205 10 1996.204.07.17.38.792 Time (ms) Red Sprites Red Sprites: - altitude range ~50-90 km - lateral extent ~5-10 km - occur ~1-5 ms after +CG discharge - last up to several 10 ms Aircraft view Ground View 90-95 km horizon Space Shuttle View sprite sprite thunderstorm Examples of Terrestrial Gamma Ray Flashes (BATSE Data) Terrestrial Gamma Rays: - time duration ~1 ms - energies 20 keV—2 MeV - hard spectrum (bremsstrahlung) Rate (counts/0.1ms) Rate (counts/0.1ms) Rate (counts/0.1ms) Time (ms) Time (ms) Time (ms) Time (ms) C. T. R. Wilson, 1925 While the electric force due to the thundercloud falls off rapidly, ... the electric force required to cause sparking ... falls off still more rapidly. Thus, ... there will be a height above which the electric force due to the cloud exceeds the sparking limit .. -
What Are Lichtenberg Figures and How Are They Created? Copyright 2010, Bert Hickman
What are Lichtenberg Figures and how are they created? Copyright 2010, Bert Hickman Lichtenberg Figures are branching, tree-like patterns that are sometimes formed on the surface or inside insulating materials by high voltage electrical discharges. The first Lichtenberg Figures were two-dimensional patterns formed in dust on charged insulating plates by the German physicist who discovered them, Georg Christoph Lichtenberg (1742-1799). The principles involved in the formation of these early figures are also fundamental to the operation of modern copy machines and laser printers. Using modern materials and powerful particle accelerators, beautiful 3-D Lichtenberg Figures can now be created inside clear acrylic, creating lightning sculptures. We use acrylic (Polymethyl Methacrylate or PMMA) to make our Lichtenberg Figures, since it has an ideal combination of optical, electrical, and mechanical properties. We also use a linear accelerator (LINAC) to create a beam of high-speed electrons. Electrons in the beam are accelerated to as much as 99.5% of the speed of light. These “relativistic” electrons have a very large amount of kinetic energy, measured in millions of electron Volts (MeV). Polished acrylic specimens are placed in the path of the beam. As the high speed electrons hit the acrylic surface, they don’t stop immediately. Instead, they collide with acrylic molecules, rapidly slowing down, eventually coming to rest deep inside the acrylic. As we continue to irradiate the specimens, huge numbers of electrons accumulate inside, forming an invisible cloud-like layer of excess negative charge. Since acrylic is an excellent electrical insulator, the excess electrons are trapped within the charge layer. -
Bibliography
Bibliography F.H. Attix, Introduction to Radiological Physics and Radiation Dosimetry (John Wiley & Sons, New York, New York, USA, 1986) V. Balashov, Interaction of Particles and Radiation with Matter (Springer, Berlin, Heidelberg, New York, 1997) British Journal of Radiology, Suppl. 25: Central Axis Depth Dose Data for Use in Radiotherapy (British Institute of Radiology, London, UK, 1996) J.R. Cameron, J.G. Skofronick, R.M. Grant, The Physics of the Body, 2nd edn. (Medical Physics Publishing, Madison, WI, 1999) S.R. Cherry, J.A. Sorenson, M.E. Phelps, Physics in Nuclear Medicine, 3rd edn. (Saunders, Philadelphia, PA, USA, 2003) W.H. Cropper, Great Physicists: The Life and Times of Leading Physicists from Galileo to Hawking (Oxford University Press, Oxford, UK, 2001) R. Eisberg, R. Resnick, Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles (John Wiley & Sons, New York, NY, USA, 1985) R.D. Evans, TheAtomicNucleus(Krieger, Malabar, FL USA, 1955) H. Goldstein, C.P. Poole, J.L. Safco, Classical Mechanics, 3rd edn. (Addison Wesley, Boston, MA, USA, 2001) D. Greene, P.C. Williams, Linear Accelerators for Radiation Therapy, 2nd Edition (Institute of Physics Publishing, Bristol, UK, 1997) J. Hale, The Fundamentals of Radiological Science (Thomas Springfield, IL, USA, 1974) W. Heitler, The Quantum Theory of Radiation, 3rd edn. (Dover Publications, New York, 1984) W. Hendee, G.S. Ibbott, Radiation Therapy Physics (Mosby, St. Louis, MO, USA, 1996) W.R. Hendee, E.R. Ritenour, Medical Imaging Physics, 4 edn. (John Wiley & Sons, New York, NY, USA, 2002) International Commission on Radiation Units and Measurements (ICRU), Electron Beams with Energies Between 1 and 50 MeV,ICRUReport35(ICRU,Bethesda, MD, USA, 1984) International Commission on Radiation Units and Measurements (ICRU), Stopping Powers for Electrons and Positrons, ICRU Report 37 (ICRU, Bethesda, MD, USA, 1984) 646 Bibliography J.D. -
Electrical Breakdown in Gases
High-voltage Pulsed Power Engineering, Fall 2018 Electrical Breakdown in Gases Fall, 2018 Kyoung-Jae Chung Department of Nuclear Engineering Seoul National University Gas breakdown: Paschen’s curves for breakdown voltages in various gases Friedrich Paschen discovered empirically in 1889. Left branch Right branch Paschen minimum F. Paschen, Wied. Ann. 37, 69 (1889)] 2/40 High-voltage Pulsed Power Engineering, Fall 2018 Generation of charged particles: electron impact ionization + Proton Electron + + Electric field Acceleration Electric field Slow electron Fast electron Acceleration Electric field Acceleration Ionization energy of hydrogen: 13.6 eV 3/40 High-voltage Pulsed Power Engineering, Fall 2018 Behavior of an electron before ionization collision Electrons moving in a gas under the action of an electric field are bound to make numerous collisions with the gas molecules. 4/40 High-voltage Pulsed Power Engineering, Fall 2018 Electron impact ionization Electron impact ionization + + Electrons with sufficient energy (> 10 eV) can remove an electron+ from an atom and produce one extra electron and an ion. → 2 5/40 High-voltage Pulsed Power Engineering, Fall 2018 Townsend mechanism: electron avalanche = Townsend ionization coefficient ( ) : electron multiplication : production of electrons per unit length along the electric field (ionization event per unit length) = = exp( ) = = 푒 푒 6/40 High-voltage Pulsed Power Engineering, Fall 2018 Townsend 1st ionization coefficient When an electron travels a distance equal to its free path in the direction of the field , it gains an energy of . For the electron to ionize, its gain in energy should be at least equal to the ionization potential of the gas: 1 1 = ≥ st ∝ The Townsend 1 ionization coefficient is equal to the number of free paths (= 1/ ) times the probability of a free path being more than the ionizing length , 1 1 exp exp ∝ − ∝ − = ⁄ − A and B must be experimentally⁄ determined for different gases.