Download or read book Dynamics of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams, as has been demonstrated on the Neutralized Drift Compression Experiment NDCX-I and NDCX-II. This article presents experimental results on charge neutralization of a high-perveance 38 keV Ar+ beam by a plasma produced in a FEPS discharge. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable with sufficiently dense FEPS plasma. The transverse electrostatic potential of the ion beam is reduced from 15V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Measurements of the time-evolution of beam radius show that near-complete charge neutralization is established similar to -5 [mu]s after the driving pulse is applied to the FEPS and can last for 35 [mu]s. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub-mu s surface discharge. Measurements of current flow in the driving circuit of the FEPS show the existence of electron emission into vacuum, which lasts for tens of mu s after the high voltage pulse is applied. Lastly, it is argued that the beam is neutralized by the plasma produced by this process and not by a surface discharge plasma that is produced at the instant the high-voltage pulse is applied.
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 Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma written by and published by . This book was released on 2009 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutralization and focusing of intense charged particle beam pulses by a background plasma 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 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 Method of Obtaining a Neutralized Ion Beam from a Plasma Source with the Aid of a High Frequency Electric Field written by A. A. KUZOVNIKOV and published by . This book was released on 1965 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A method is described of obtaining a neutralized ion beam from a plasma source with the aid of a high frequency electric field, characterized by the fact, that for the purpose of compensating the accumulated electrostatic charge of output from source and to assure its stable operation, the accelerating electrode is maintained under a high frequency and constant voltage relative to the plasma source. By selecting the frequency of the HF voltage is assured in each half-period the ejection, into outer space from the output opening of electron and positive ion clusters, the difference in e/m for electrons and ions is compensated and an average in time delivery of electric charge, equaling zero is obtained, by the arrangement of a corresponding voltage, fed from without or maintained automatically by assuring on the accelerating electrode of a floating potential. (Author).
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 Physics and Technology of Plasma Ion Sources written by M. D. Gabovich and published by . This book was released on 1973 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: ;Contents: Brief information on certain elemental processes occurring in plasma ion sources; Plasma ion sources (basic physical processes, designs, properties, and parameters); The mass spectrum and charge composition of beams extracted from plasma ion sources; Plasma sources of ions of refractory metals; Extraction of ions and the primary formation of ion beams. Beam propagation and a study of beams; Penetration of a plasma from an ion source into a vacuum. Energy of the ions leaving the source plasma; The vibrational properties of a plasma and their influence on the processes in plasma ion sources and neutralized ion beams.
Download or read book Production and Neutralization of Negative Ion Beams written by Ady Hershcovitch and published by American Institute of Physics. This book was released on 1990 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ion beam Plasma Neutralization Interaction Images written by Igor D. Kaganovich and published by . This book was released on 2002 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Production and Neutralization of Negative Ions and Beams Eighth International Symposium Production and Application of Light Negative Ions Seventh European Workshop A Joint Meeting written by Claude Jacquot and published by American Inst. of Physics. This book was released on 1998-09-11 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising the proceedings of the September 1997 symposium (called the Symposium with the Long Name by some insiders), this volume contains 28 contributions, arranged into five sections: fundamental processes; diagnostics; sources; negative ions acceleration; and applications and systems. With act
Download or read book Ion Accumulation and Space Charge Neutralization in Intensive Electron Beams for Ion Sources and Electron Cooling written by G. D. Širkov and published by . This book was released on 1996 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Simulations of Ion Beam Neutralization in Support of Theneutralized Transport Experiment written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Heavy ion fusion (HIF) requires the acceleration, transport, and focusing of many individual ion beams. Drift compression and beam combining prior to focusing result in [approx]100 individual ion beams with line-charge densities of order 10[sup -5] C/m. A focusing force is applied to the individual ion beams outside of the chamber. For neutralized ballistic chamber transport (NBT), these beams enter the chamber with a large radius (relative to the target spot size) and must overlap inside the chamber at small radius (roughly 3-mm radius) prior to striking the target. The physics of NBT, in particular the feasibility of achieving the required small spot size, is being examined in the Neutralized Transport Experiment (NTX) at Lawrence Berkeley National Laboratory. Interpreted by detailed particle-in-cell simulations of beam neutralization, experimental results are being used to validate theoretical and simulation models for driver scale beam transport. In the NTX experiment, a low-emittance 300-keV, 25-mA K[sup +] beam is focused 1 m downstream into a 4-cm radius pipe containing one or more plasma regions. The beam passes through the first 10-cm-long plasma, produced by an Al plasma arc source, just after the final focus magnet and propagates with the entrained electrons. A second, 10-cm-long plasma (produced with a cyclotron resonance plasma source) is created near focus to simulate the effects of a photo-ionized plasma created by the heated target in a fusion chamber. Given a 0.1-[pi]-mm-mrad beam emittance, two and three-dimensional particle-in-cell (PIC) LSP simulations of the beam neutralization predict a
Download or read book Simulations of Ion Beam Neutralization in Support of Theneutralized Transport Experiment written by D. V. Rose and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Heavy ion fusion (HIF) requires the acceleration, transport, and focusing of many individual ion beams. Drift compression and beam combining prior to focusing result in {approx}100 individual ion beams with line-charge densities of order 10{sup -5} C/m. A focusing force is applied to the individual ion beams outside of the chamber. For neutralized ballistic chamber transport (NBT), these beams enter the chamber with a large radius (relative to the target spot size) and must overlap inside the chamber at small radius (roughly 3-mm radius) prior to striking the target. The physics of NBT, in particular the feasibility of achieving the required small spot size, is being examined in the Neutralized Transport Experiment (NTX) at Lawrence Berkeley National Laboratory. Interpreted by detailed particle-in-cell simulations of beam neutralization, experimental results are being used to validate theoretical and simulation models for driver scale beam transport. In the NTX experiment, a low-emittance 300-keV, 25-mA K{sup +} beam is focused 1 m downstream into a 4-cm radius pipe containing one or more plasma regions. The beam passes through the first 10-cm-long plasma, produced by an Al plasma arc source, just after the final focus magnet and propagates with the entrained electrons. A second, 10-cm-long plasma (produced with a cyclotron resonance plasma source) is created near focus to simulate the effects of a photo-ionized plasma created by the heated target in a fusion chamber. Given a 0.1-{pi}-mm-mrad beam emittance, two and three-dimensional particle-in-cell (PIC) LSP simulations of the beam neutralization predict a
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 Plasma Neutralization Models for Intense Ion Beam Transport in Plasma written by and published by . This book was released on 2003 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed based on the assumption of long charge bunches (l{sub b}” r{sub b}). Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The analytical predictions for the degree of ion beam charge and current neutralization also agree well with the results of the numerical simulations. The model predicts very good charge neutralization (>99%) during quasi-steady-state propagation, provided the beam pulse duration [tau]{sub b} is much longer than the electron plasma period 2[pi]/[omega]{sub p}, where [omega]{sub p} = (4[pi]e2n{sub p}/m)12 is the electron plasma frequency, and n{sub p} is the background plasma density. In the opposite limit, the beam pulse excites large-amplitude plasma waves. The analytical formulas derived in this paper can provide an important benchmark for numerical codes, and provide scaling relations for different beam and plasma parameters.
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.
