Download or read book Modified Betatron Accelerator Studies written by T. P. Hughes and published by . This book was released on 1983 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of an extensive study of the modified betatron accelerators are reported. The topics are beam injection, equilibrium and stability. Three-dimensional particle simulations of injections were performed. The results show good agreement with theory. Various types of equilibria were studied using two dimensional simulations. Results are compared to the calculations of Finn and Manheimer. Beam stability is investigated using a combination of analytic and numerical techniques. Growth rates of the negative mass, resistive wall, beam breakup, and image displacement instabilities are calculated. A new theory of the negative mass instability, keeping toroidal corrections to Maxwell's equations, is derived. Good agreement between theory and simulations is obtained. The negative mass instability is shown to be the dominant instability. Simulations show that it can disrupt the beam in a time of order one microsecond. Stabilization may require a beam of large minor radius. Work on the other instabilities show that measures can be taken to make their effect negligible. (Author).
Download or read book Cantate auf die Reformations Feier der studierenden Jugend in Z rich written by and published by . This book was released on 1819 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Synchrotron Radiation Emission from the NRL Modified Betatron Accelerator written by and published by . This book was released on 1991 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical calculations of synchrotron radiation emitted from the NRL modified betatron accelerator show that, for relativistic electron energies up to approximately 2 MeV, the single particle intensity spectrum is characterized by a peak at the Doppler-shifted cyclotron frequency associated with applied toroidal field. Measurements of the radiation using fixed-frequency heterodyne receivers indicate that the polarization, amplitude, and the temporal evolution of radiated power during acceleration are in very good agreement with the predicted single particle spectrum. The observations have been used to confirm the energy evolution and provide information about the magnitude of the transverse velocity of the beam electrons for the first few hundred microseconds of acceleration. Late-time signal decay suggests that electrons are moving off the minor axis in a manner that is consistent with the excitation of the electron-cyclotron resonance.
Download or read book High Brightness Accelerators written by Anthony D. Hyder and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt: A NATO Advanced Study Institute (ASI) on High-Brightness Accelerators was held at the Atholl Palace Hotel, Pitlochry, Perthshire, Scotland, from July 13 through July 25, 1986. This publication is the Proceedings of the Institute. This ASI emphasized the basic physics and engineering of the rela tively new and fast-emerging field of high-brightness particle accelera tors. These machines are high- to very-high-current (amperes to hundreds of kiloamperes), modest-voltage (megavolt to tens of megavolts) devices, and as such are opposed to those historically used for high-energy physics studies (i.e., gigavolt and higher energies and rather low currents). The primary focus of the Institute was on the physics of the accelerator and the beam, including the dynamics, equilibria, and insta bilities of high-current beams near the space-charge limit; accelerator engineering techniques; and the applications of high-brightness beams in areas such as free-electron lasers, synchrotron-radiation sources, food processing, and heavy- and light-ion fusion. The Institute concentrated on bringing together several diverse but related communities which, we hope, benefited from this opportunity to interact: the North American activity in machine technology, engineer ing, and diagnostics with the strong European theoretical community; the basic beam physicists with the engineering technologists.
Download or read book Studies of the Integer Cyclotron Resonances in a Modified Betatron Accelerator written by and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper briefly summarizes recent experimental results from the studies of the integer cyclotron resonances in the NRL modified betatron accelerator. Special emphasis is given to the l = 12 resonance, because the NRL device has a twelve-fold symmetry. To test the importance of the l = 12 resonance, we have intentionally introduced an l = 12 field error using twelve resonant coils. By activating these coils when the resonance is observed, the duration of x-rays produced by beam loss was reduced from 900 microsecond to 5.5 microsecond, while the amplitude of the signal increased from 0.5 to about 40 volts. The full width of the x-ray pulse at half maximum is inversely proportional to the current through the resonant coils and proportional to the risetime of the pulse. Work is in progress with a set of twelve internal coils that have a risetime of 300-400 ns. Studies of the spatial distribution of beam losses at l = 12 show that the beam is always lost in six well defined toroidal positions. In addition, it has been shown experimentally that when the ratio of the total toroidal magnetic field to the vertical field is not an integer, the cyclotron resonance is not excited.
Download or read book The Modified Betatron Accelerator Experiment written by F. M. Mako and published by . This book was released on 1984 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents: A Free Electron Laser Driven by a Long Pulse Induction Linac; Special Focus Program Advanced Accelerator Modified Betatron Design REview Coil DEsign; External Injection into a High Current Modified Betatron Accelerator; Electron Drift in a Linear Magnetic Wiggler with an Axial Guide Field; A Broadband High Power Millimeter to Centimeter Spectrometer; Electron Drift in a LInear Magnetic Wiggler with an Axial Guide Field; Numerical Simulation of High Energy Light Ion Beam Flow Through a Foilless Diode; and High Current, High Voltage Accelerators as Free-Electron Lasers Drivers.
Download or read book Non Linear Transverse Electron Beam Dynamics in a Modified Betatron Accelerator written by C. A. Kapetanakos and published by . This book was released on 1984 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transverse electron beam dynamics in a modified betatron accelerator is studied using a new approach. This approach is based on the two exact constants of the motion and the potentials at the center of the beam. The main advantage of the present technique is that the ring orbits can be accurately determined over the entire minor cross-section of the torus and not only near the minor axis. Results indicate that the electron ring orbits, in the plane transverse to the toroidal magnetic field, always close inside the vacuum chamber and their topology is often substantially different than that predicted from the linear theory. (Author).
Download or read book Injection of a High Current Beam Into a Modified Betatron Accelerator written by C. A. Kapetanakos and published by . This book was released on 1982 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method is proposed for injecting and trapping a high current, high energy, nonneutral electron beam into a modified betatron accelerator. The injection is substantially simplified as a result of the balancing of two effects that are prominent in high current beams. (Author).
Download or read book High Current Betatron Stability and Injection Studies written by T. P. Hughes and published by . This book was released on 1983 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: MRC Contributing In Several Areas of High Current Cyclic Induction Accelerator Research: (1) Linear Theory of Negative Mass and Resistive, Wall Instabilities in Modified Betatron, (2) Linear Theory of Beam Breakup Instability in Recirculating Induction Accelerator, (3) Single-Turn Injection Simulation for Modified Betatron, (4) Multi-Turn Injection Simulation for Conventional Betatron, and (5) Negative Mass Instability Saturation Simulation. Presentation reviews negative mass saturation, negative mass linear theory, multi-turn injection.
Download or read book External Injection Into a High Current Modified Betatron Accelerator written by F. Mako and published by . This book was released on 1983 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: By axially tapering the current density at each end of an axial pinch a scheme is developed for injecting electrons across magnetic field lines into a modified betatron accelerator. This scheme produces only a minimal perturbation to the circulating electron beam. The axial pinch provides beam equilibrium in the transverse field and the tapering reduces the non-adiabatic growth of the perpendicular particle velocity from 0.5 c to .05 c for the parameters of the NRL modified betatron. (Author).
Download or read book Equilibrium of a High Current Electron Ring in a Modified Betatron Accelerator written by C. A. Kapetanakos and published by . This book was released on 1982 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper addresses the dynamics of an ultra-high current electron ring in a modified betatron configuration. Our studies include analytical and numerical results for both 'cold' and 'hot' rings. It has been found that the walls surrounding the ring and toroidal effects (hoop stresses) play a very important role in the dynamics of the ring, even when the wall conductivity is infinite. For finite wall conductivity, the diffusion of the ring's self magnetic field profoundly impacts its dynamics in general the equilibrium could be lost if means are not provided to compensate for this effect. In addition, it has been found that the Grad B drift is not important, except when the bounce frequency is very small. The general conclusion of these studies is that equilibrium states of ultra-high current rings in a modified betatron configuration exist over a wide range of parameters. These states are accessible and within the realm of existing pulsed power technology.
Download or read book Ion Resonance Instability in a Modified Betatron Accelerator written by Han S. Uhm and published by . This book was released on 1981 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Field Index Fluctuations on the Dynamics of a High Current Electron Ring in a Modified Betatron Accelerator written by C. Agritellis and published by . This book was released on 1983 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analytical and computer simulation results are reported on the effect of the external field index fluctuations on the dynamics of a high current electron ring in a modified betatron. These non-linear studies clearly demonstrate that the external field index fluctuations are, in general, harmless to the high current ring. In addition, it was found that a small (1%) temperature spread parallel to the direction of propagation excites oscillations in the rms emittance, but the amplitude of these oscillations is substantially lower than in a conventional betatron. (Author).
Download or read book Recirculating Accelerator Studies written by Thomas P. Hughes and published by . This book was released on 1987 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results of stability calculations for three types of high current betatron (modified betatron, stellatron, solenoidal lens betatron) are presented. For the modified betatron, stability is strongly dependent on the internal poloidal rotation frequency of the beam. When this frequency is close to zero, high-mode numbers are easily stabilized. For the NRL betatron parameters, the beam is predicted to become unstable when it accelerates above 1 MeV. For a 10 kA beam, several kiloamps remain circulating after saturation of the instability. High energy simulations of the modified betatron show saturation without loss of current. Calculations for the stellatron show that background ions have a strong stabilizing effect on the negative mass instability, due to increased transverse focusing. The energy threshold for onset of instability agrees with experimental observation. An electromagnetic three wave interaction is found to occur in the stellatron. Its growth rate can be very large, but parameters can be chosen to move it to short wavelengths where thermal effects should stabilize it. An anlaytic dispersion relation for the solenoidal lens betatron is obtained using a multiple length scaled averaging method. The betatron is predicted to be stable at and slightly above its injection energy. Simulation for higher energy show a strong instability which substrates with some loss of current. Simulations of 10 kA beams in a solenoidal lens betatron show similar results, suggesting that most of the current can survive the instability.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of the Electron Ring Dynamics in a Modified Betatron for Large Ring Displacements from the Minor Axis written by S. J. Marsh and published by . This book was released on 1987 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: A two dimensional 3V particle in cell (PIC) computer code is used to study the electron ring dynamics in a magnetic field configuration that is very similar to that of the modified betatron experiment. The electron ring dynamics has been simulated over approximately seventy five revolutions around the major axis, i.e., over several bounce periods. By comparing the electron ring dynamics in an idealized magnetic fields with that in the experiment, it has been determined that the field index spatial fluctuations that occur in the experiment are harmless to high current rings. In addition, the computer simulation results have confirmed our theoretical predictions concerning the variations of the ring's equilibrium position with the vertical field as well as the existence, in the ring centroid instability gap, of ring orbits having figure eight (8) shape. Keywords: High current accelerators; Modified Betatron: Computer simulation; Budker Parameter.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt:
