Download or read book Propagation of a Neutralized Ion Beam written by Norman Rostoker and published by . This book was released on 1991 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beam propagation experiments were performed with various plasma sources to understand the physics of plasma motion in a transverse magnetic field and magnetic diffusion in a plasma. High-beta hydrogen beams propagated by ExB drift at their initial velocity. Low-beta plasmas showed initial ExB drift, followed by deceleration, transverse compression and thermalization of the beam energy. A wide range of diamagnetism was observed. Magnetic diffusion times were consistent with those based on Hall conductivity.
Download or read book EXOATMOSPHERIC PROPAGATION OF NEUTRALIZED ION BEAMS written by A.T. DROBOT and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ion Beam Propagation in a Solenoidal Magnetic Field written by J. J. Moschella and published by . This book was released on 1984 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study of an intense space charge neutralized ion beam propagating into a solenoidal magnetic field is presented. The data shows that the observed effects are adequately described by a theory for beam propagation. In a previous experiment a similar beam was focused by a short magnetic field where the focal point was outside the field region. This experiment shows that the same theory can be used to describe a beam which comes to a focus within the uniform region of the solenoid. The theory essentially states that ions undergo single particle motion modified by the beam neutralizing electrons which produces focal distances much shorter than ions acting alone. The physics of this type of focusing is similar to the Gabor lens in which electrons that prefill a magnetic mirror produce electrostatic fields which assist in the focusing of a stream of ions. The new theory, assumes a cylindrically symmetric beam which does not significantly perturb the magnetic field, maintenance of local space charge neutrality and perfectly cold neutralizing electrons. (jhd).
Download or read book Charged Particle Beams written by Stanley Humphries, JR. and published by Courier Corporation. This book was released on 2013-04-04 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed enough to serve as both text and reference, this volume addresses topics vital to understanding high-power accelerators and high-brightness-charged particle beams, including stochastic cooling, high-brightness injectors, and the free electron laser. 1990 edition.
Download or read book Propagation of Neutralized Ion Beams written by Amnon Fisher and published by . This book was released on 1987 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The propagation of plasmoids (neutralized beams) in a vacuum transverse magnetic field has been studied in the UCI laboratory for several years. The most recent experiments are aimed at studying the plasmoid propagation dynamics and losses in the presence of a background, magnetized plasma which is intended to short the induced polarization electric field and stop the beam. Preliminary results indicate that the beam propagation losses increase with the background plasma density. Principal diagnostics include: magnetically insulated Faraday cups, floating potential probes, calorimeters, microwave interferometer, and thermal-witness paper. Experiments in the near future will use an improved accelerator and transverse-field coil system which allows higher energy, 500 keV, higher current density plasmoids to be studied; this generator will improve the beam uniformity and angular divergence to allow beam propagation for up to five meters and permit study of losses from surface erosion. Keywords: Plasmoids; Propagation; Magnetic field.
Download or read book Intense Pulsed Ion Beam Neutralization Focusing and Collective Plasma Interactions written by Robert Kraft and published by . This book was released on 1985 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this thesis is to study the propagation of an intense pulsed ion beam in certain environments. Three areas of ion beam propagation are studied: charge and current neutralization by electrons when a beam is injected into a vacuum region; focusing of a beam when it is axially injected into a solenoidal magnetic lens; and collective interactions when a beam passes through a background hydrogen plasma. The experimentally observed beam behavior in each of these situations is analyzed and compared with theoretical models. In the experiment, a beam (360 keV., 65 amps/sq cm, 150 ns.) was extracted from a planar, magnetically insulated diode and injected into a field free vacuum region. The beam was found to be both charge and current neutralized by electrons drawn axially into the beam from the cathode of the diode. The neutralization process was modelled with a theory which predicts the velocity distribution of the comoving neutralizing electrons. (jhd).
Download or read book Physics of Neutralization of Intense High Energy Ion Beam Pulses by Electrons written by and published by . This book was released on 2010 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutralization and focusing of intense charged particle beam pulses by electrons forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self- magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the background plasma. If controlled, this physical effect can be used for optimized beam transport over long distances.
Download or read book Symmetric Neutralized Ion Beams written by Nathaniel Kenneth Hicks and published by . This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation presents the first integrated experimental, computational, and theoretical research program on symmetric neutralized ion beams. A beam of this type is composed of positive and negative ions having equal charge-to-mass ratios, such that the beam has overall charge neutrality and its constituent ions respond symmetrically to electromagnetic forces. Under the right conditions, these beams may propagate undeflected across transverse magnetic fields due to beam polarization. Such propagation is studied here computationally, using a three-dimensional particle-in-cell code. Also, key theoretical differences between the propagation ability of these beams and that of beams consisting of positive ions and electrons are elucidated.
Download or read book Intense Ion Beam Propagation in a Reactor Sized Chamber written by and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors consider the physics of the ballistic transport of intense ion beams in a heavy ion fusion reactor chamber filled with low pressure FLIBE gas. The authors consider first a single beam envelope model and show via a simple case that emittance growth is an issue in the chamber as well as in the accelerator. They develop a model for the neutralization of beam space-charge by the electrons produced by gas ionization by the beam and derive an expression for the evolution of the neutralization factor as the beam propagates into the chamber. They then extend the envelope model from a one species beam to a beam of ions of several charge states by considering the entire beam as a set of subbeams (one for each charge state) each described with coupled envelope equation. The fully electromagnetic PIC code BPIC was used to investigate the behavior in greater detail. A parametric study of the sensitivity of the final spot radius at the target versus the ion beam stripping and gas ionization cross-sections (which are characterized by large uncertainties) shows that, in the studied regime (Hylife-II parameters), the accessible window of cross-sections for ballistic transport in the chamber through neutral FLIBE gas is eventually small. The temperature evolution for each species and the emittance growth for the entire ion beam was studied for a typical scenario and indicates that a fair amount of the initial electric potential energy carried by the beam as it enters the chamber is converted into temperature and transverse emittance. The high temperature of the ionization-produced electrons prevents a full charge neutralization of the ion beam as it approaches the target. It is shown that focusing a beam array or pre-ionizing a fraction of the background gas may help in reducing the focal spot.
Download or read book Method of Active Charge and Current Neutralization of Intense Ion Beams for ICF written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of generating the beam neutralization electrons with required properties are given in the context of a Light Ion Fusion Experiment (LIFE) designed accelerator. Recently derived envelope equations for neutralized and ballistically focused intense ion beams are applied to the LIFE geometry in which 10 MeV He multiple beamlets coalesce and undergo 45:1 radial compression while beam pulses experience a 20:1 axial compression in the propagation range of 10 m. Both active and auto-neutralization methods are examined and found to produce initial electron temperatures consistent with the requirement of the envelope equation for both radial and axial adiabatic beam pulse compressions. The stability of neutralized beam propagation is also examined concerning the Pierce type electrostatic instability and for the case of LIFE beams it is found to have insignificant effect. A scaled experimental setup is presented which can serve to perform near term tests on the ballistically focused propagation of neutralized light ion beams.
Download or read book Propagation of Ion Beams Through a Tenuous Magnetized Plasma written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: When an ion beam is propagated through a plasma, the question of charge neutralization is critical to its propagation. We consider such a problem where the plasma is magnetized with magnetic field perpendicular to the beam. The plasma-number density and beam-number density are assumed comparable. We reduce the problem to a two-dimensional model, which we solve. The solution suggests that it should be possible to attain charge neutralization if the beam density is properly varied along itself.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Magnetic Field Penetration Into an Intense Neutralized Ion Beam written by and published by . This book was released on 1992 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments involving propagation of neutralized ion beams across a magnetic field indicate a magnetic field penetration time determined by the Hall resistivity rather than the Spitzer or Pedersen resistivity. In magnetohydrodynamics the Hall current is negligible because electrons and ions drift together in response to an electric field perpendicular to the magnetic field. For a propagating neutralized ion beam, the ion orbits are completely different from the electron orbits and the Hall current must be considered. There would be no effect unless there is a component of magnetic field normal to the surface which would usually be absent for a good conductor. It is necessary to consider electron inertia and the consequent penetration of the normal component to a depth c/[omega]{sub p}. In addition it is essential to consider a component of magnetic field parallel to the velocity of the beam which may be initially absent, but is generated by the Hall effect. The penetration time is determined by whistler waves rather than diffusion.
Download or read book Nonlinear Charge and Current Neutralization of an Ion Beam Pulse in a Pre formed Plasma written by Igor D. Kaganovich and published by . This book was released on 2001 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microwave and Particle Beam Sources and Propagation written by Norman Rostoker and published by . This book was released on 1988 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Charge and Current Neutralization Physics of a Heavy Ion Beam During Final Transport written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Heavy ion fusion requires high power to be focussed onto a small pellet. If the reactor chamber pressure is below 10−4 to 10−5 Torr, beam compression will be limited by space charge unless neutralized by co-moving electrons. If higher chamber pressures are used, the heavy ion beam will create a significant number of background electrons during its propagation and will undergo stripping. The background electrons could provide the neutralization required for high beam intensities. In this paper we will focus on the physics associated with propagation through a fully ionized hydrogen plasma, so background electron generation is not included. One-dimensional electrostatic and two-dimensional fully electromagnetic particle-in-cell simulations are presented. If a background plasma is present, we find that coinjected electrons whose purpose is to charge and current neutralize the ion beam become two-stream unstable and no longer provide the thermally cool neutralization required. Further, we find that the ion induced background electron temperature is very sensitive to the ion beam to background electron charge density ratio.
Download or read book THE PROPAGATION DISTANCE OF THE BY PRODUCT ION BEAM EMITTED FROM NEUTRAL PARTICLE BEAM ACCELERATOR written by J.E. BOROVSKY. and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
