Computer experiments on ion-beam neutralization with initially cold electrons

Dunn, D. A.; Ho, Ian

doi:10.2514/3.2171

Cited by 32 publications

(4 citation statements)

References 10 publications

(10 reference statements)

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“…The probability given by (37) is evaluated for all the particles at every time step from the quantities U' (&,), vz(tn). After this calculation is made the decision has to be reached as to which particles should suffer collisions.…”

Section: Early Workon Simulation Eleciron-neutral Elastic Collisionsmentioning

confidence: 99%

“…. coarse-graining in space was first used by Dunn and Ho [37] and it was also applied by Hockney for the computer model of a two-dimensional plasma [47]. "…”

Section: Hockney and Eastwoodmentioning

confidence: 99%

“…They appear in the references as Birdsall and Bridges [7], Dunn [37], Hockney and Eastwood [50], Birdsall and Langdon [12], Tajima [82]. There are three review books (vols.…”

mentioning

confidence: 99%

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Particle-in-cell charged-particle simulations, plus Monte Carlo collisions with neutral atoms, PIC-MCC

Birdsall

1991

IEEE Trans. Plasma Sci.

1,219

817

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Many-particle (meaning 1OOO's) charged-particle plasma simulations using spatial meshes for the electromagnetic field solutions, particle-in-cell (PIC) merged with Monte Carlo collision (MCC) calculations, are coming into wide use for application to partially ionized gases. This paper emphasizes the development of PIC computer experiments since the 1950's starting with one-dimensional (1-D) chargedsheet models, the addition of the mesh, and fast direct Poisson equation solvers for 2-D and 3-D. The finite-size particle-in-mesh (finite AZ, At) theory of Langdon [51]-[53] is presented in part to display the effects of too small Ao/Ax, even for Maxwellian velocity distributions, as a caution, for example, when some ions are cooled to background gas temperatures by charge exchange. Early work on adding collisions to 1-D chargesheet models by Burger [28] and Shanny et aL[76] are presented, with many of the elements of current Monte Carlo codes. Bounded plasma modeling is presented with electrode charges and external R, L, C, and V(t), Z(t) sources now in use on fast desktop computers as real-time computer experiments, complementing analytic modeling and laboratory experiments. The addition of Monte Carlo collisions (usually done with irregular timesteps) to PIC (usually done with uniform At's) is displayedas a developing art, relying on experimental total cross sections and approximate analytical differential cross sections to produce changes in charged-particle speed and direction due to collisions with neutrals, so far including elastic, excitation, ionization, charge exchange, and attachment processes. r. INTRODUCTIONHE plasma medium, consisting of electrons, ions, neutral T atoms and molecules, and particles, is very complicated to understand. Theory and modeling provide guide-lines for design of devices; experiments provide a variety of measurements.Simulations provide insight, and numbers, computer experiments. Interactions among this trio have proven effective and efficient in advancing plasma science and engineering.This report leads the reader through the development over the past four decades of many-particle particle-in-cell (PIC) simulations and into including charged-particle collisions with neutral atoms using Monte Carlo methods. Some mention will be made of doing Coulomb collisions using PIC codes. We then provide some details of adding the collisions between the charged particles and neutral atoms. The result is many-particle simulations with many of the features met in low-temperature collisional plasmas; for example, with applications to plasmaassisted materials processing, but also related to warmer plasmas at the edges of magnetized fusion plasmas.Collisionless many-particle plasma simulation is rich in history and may rate as one of the success stories in physics and engineering using the modern digital computer, along with such advances as numerical wind tunnels and space craft control and communications-both complementing theory and experiment and, in some cases, being the main ingredient. This ...

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Section: Early Workon Simulation Eleciron-neutral Elastic Collisionsmentioning

confidence: 99%

“…. coarse-graining in space was first used by Dunn and Ho [37] and it was also applied by Hockney for the computer model of a two-dimensional plasma [47]. "…”

Section: Hockney and Eastwoodmentioning

confidence: 99%

See 1 more Smart Citation

Particle-in-cell charged-particle simulations, plus Monte Carlo collisions with neutral atoms, PIC-MCC

Birdsall

1991

IEEE Trans. Plasma Sci.

1,219

817

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“…Earlier theoretical and simulations models have considered the neutralization of infinitively large uniform ion beam [2,3,4,5,6]. More recent models have considered a more realistic setting for finite size ion beam emission [7,8,9].…”

Section: Introductionmentioning

confidence: 99%

Kinetic Simulations of Ion Beam Neutralization

Chang

Wang

2011

AIP Conference Proceedings

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Full particle PIC simulations are performed to study the neutralization of an ion beam in the cohesionless, mesothermal regime. Simulations further confirmed that neutralization is achieved through interactions between the trapped electrons and the potential well established by the propagation of the beam front along the beam direction and is not through plasma instabilities as previous studies suggested. In the transverse direction, the process is similar to that of the expansion of mesothermal plasma into vacuum. Parametric simulations are also performed to investigate the effects of beam radius and domain boundary condition on the neutralization process. The results suggests that, while the qualitative behavior may be similar in ground tests, quantitative parameters such as the beam potential will be affected significantly by the vacuum chamber because of the limits imposed on the expansion process by the finite chamber space.

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Remarks on the Poukey‐Rostoker‐model of relativistic electron beam propagation

Hantzsche

1975

Contrib Plasma Phys

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Some properties of an analytic electrostatic model of relativistic electron beam propagation in vacuum, developed by POUKEY and ROSTOKER [l] Introductory remarksThe propagation of relativistic electron beams depends on the geometric conditions, on their own electric and magnetic fields, on the degree of charge neutralisation, on external fields and on the gas resp. plasma, which they penetrate. Several models have been developed to solve this complicated task at least partly and approximately, e.g. I n one of the simplest cases, the purely electrostatic, onedimensional movement of electrons in field-free vacuum , a self-consistent analytic solution has been given by POUKEY and ROSTOKER [ 11 who use a single-particle model with Lagrangian description of the motion. Because of the great simplicity and transparency of this model a more careful and detailed study of its characteristics and its limits may be of interest.After a description of the equations and main results of the model -this is largely a repetition from [l] -we discuss the most important "events" in the beam: the reflection, the mixing and backflow of electrons, as well as the distribution of potential and space charge. In this way the limits of validity of the model are exactly determined, and the procedures to overcome this limitation is indicated. Equations of the modelWe assume: The cathode may be located at z = 0, where the electrons at the time T = To enter the half-space X > 0 with the velocity V = Vo and the density N = No.There is no dependence of physical quantities on the other coordinates (fig. 1) ; magnetic fields are not taken into account. 12*

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Computer experiments on ion-beam neutralization with initially cold electrons

Cited by 32 publications

References 10 publications

Particle-in-cell charged-particle simulations, plus Monte Carlo collisions with neutral atoms, PIC-MCC

Particle-in-cell charged-particle simulations, plus Monte Carlo collisions with neutral atoms, PIC-MCC

Kinetic Simulations of Ion Beam Neutralization

Remarks on the Poukey‐Rostoker‐model of relativistic electron beam propagation

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