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AbstractAbstract

[en] Determination of the parameters Z/sub eff/, electrical conductivity, plasma density, and the plasma temperature is essential in the study of heavy ion beam transport in gas. The calculation of these parameters require input from atomic physics. This note is an attempt to make these needs known to atomic physicists

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Smith, L.W. (ed.); Brookhaven National Lab., Upton, NY (USA); p. 50-51; Feb 1978; p. 50-51; Heavy Ion Fusion Workshop; Upton, NY, USA; 17 - 21 Oct 1977

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AbstractAbstract

[en] This paper is concerned with intense electron beams, typically of the order of a few kA in current and up to tens of MeV in beam energy. A beam of this kind can be produced from induction machines, examples of which are the ERA (4 MeV, 1 kA) at Lawrence Berkeley Laboratory and the ASTRON (5 MeV, 500A), ETA (5 MeV, 10 kA), and ATA (50 MeV, 10 kA) at Lawrence Livermore National Laboratory (LLNL). The emphasis of the paper is on the characteristics of these beams and some applications. 13 refs., 2 figs

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20 Oct 1987; 11 p; US-CERN topical course on frontiers of particle beams; South Padre Island, TX (USA); 23-29 Oct 1987; CONF-8710228--1; Available from NTIS, PC A03/MF A01; 1 as DE88002456; Portions of this document are illegible in microfiche products.

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AbstractAbstract

[en] Determination of the parameters Z/sub eff/, electrical conductivity, plasma density, and the plasma temperature is essential in the study of heavy ion beam transport in gas. The calculation of these parameters require input from atomic physics. This note is an attempt to make these needs known to atomic physicists

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3 Nov 1977; 9 p; Heavy ion fusion workshop; Upton, NY, USA; 17 - 21 Oct 1977; CONF-771073--2; Available from NTIS., PC A02/MF A01

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AbstractAbstract

[en] The basic set of equations is derived for the calculation of the time-dependent electrical conductivity of an initially unionized gas generated by a propagating relativistic electron beam. In contrast with previous work, which used thermal averages, conductivity is determined from the complete, nonequilibrium electron energy distribution. The evolution of the distribution function, resulting from interaction with gas molecules, ions, beam induced electric field, and beam current, is described by a Boltzmann equation

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11 Aug 1978; 34 p; Available from NTIS., PC A03/MF A01

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AbstractAbstract

[en] A semi-phenomenological formula is proposed for the change of emittance of a self-pinched beam which is not matched to its equilibrium radius. Near equilibrium this formula, coupled with an envelope equation, yields the damped sausage oscillations observed in simulation and experiments. For a beam which is injected cold (no transverse velocity spread), the formula coincides with the analytically calculated initial growth of emittance. The basic theory is developed here and used to compute the linear damping rate for several current profiles. The resultant non-linear increase in equilibrium quantities is also calculated in lowest order of the degree of mismatch

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3 Dec 1979; 24 p; Available from NTIS., PC A02/MF A01

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Teague, M.R.; Yu, S.S.

Lawrence Livermore National Lab., CA (USA)

Lawrence Livermore National Lab., CA (USA)

AbstractAbstract

[en] A numerical simulation has been constructed to obtain a detailed, quantitative estimate of the electromagnetic fields generated in a recently-proposed collective accelerator scheme for electrons. The code treats the secondary electrons by particle simulation and the beam dynamics by a time-dependent envelope model. The simulation gives a fully relativistic description of secondary electrons moving in selfconsistent electromagnetic fields. The calculations are made using coordinates t, x, y, z for the electrons and t, ct-z, r for the axisymmetric electromagnetic fields and currents. Code results showing the axial electric field dependence on the configuration of the ultrashort U.V. laser pulse will be given. 4 refs., 4 figs

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14 Aug 1985; 10 p; Particle accelerator conference; Vancouver (Canada); 13-16 May 1985; CONF-850504--296; Available from NTIS, PC A02/MF A01 as DE86001651

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Yu, S.S.; Melendez, R.E.

Lawrence Livermore National Lab., CA (USA)

Lawrence Livermore National Lab., CA (USA)

AbstractAbstract

[en] A model is proposed to account for the phenomenon of net current enhancement at high pressures recently observed on the Experimental Test Accelerator. The proposed mechanism involves energetic secondary electrons (delta rays) which are pushed forward by the self-magnetic field of the electron beam. For high current beams, the forward delta ray current can build up to a significant fraction of the beam current. Analytic calculations of the steady-state solution as well as the rate of buildup of the delta ray current are presented in this paper. In addition, numerical results from a nonlocal Boltzmann code, NUTS, are presented. The analytic and numerical results have many features which are in qualitative agreement with the experiments, but quantitative discrepancies still exist

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5 Apr 1983; 58 p; Available from NTIS, PC A04/MF A01 as DE84005059

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Numerical Data

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Yu, S.S.; Melendez, R.E.

Lawrence Livermore National Lab., CA (USA)

Lawrence Livermore National Lab., CA (USA)

AbstractAbstract

[en] The mathematical framework for the LLNL code NUTS is developed. This code is designed to study the evolution of an electron-beam-generated plasma channel at all pressures. The Boltzmann treatment of the secondary electrons presented include all inertial, nonlocal, electric and magnetic effects, as well as effects of atomic collisions. Field equations are advanced simultaneously and self-consistently with the evolving plasma currents

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3 Jan 1983; 24 p; Available from NTIS, PC A02/MF A01 as DE83008310

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Yu, S.S.; Melendez, R.E.

Lawrence Livermore National Lab., CA (USA)

Lawrence Livermore National Lab., CA (USA)

AbstractAbstract

[en] The Townsend ionization coefficient in the strong runaway regime is calculated within the framework of the two-term expansion. Results are compared to the 1-D model. General features of the two models are qualitatively similar, but quantitative differences by factors of approx. 2 are observed

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15 Jul 1982; 14 p; Available from NTIS., PC A02/MF A01 as DE82020362

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Teague, M.R.; Yu, S.S.

Lawrence Livermore National Lab., CA (USA)

Lawrence Livermore National Lab., CA (USA)

AbstractAbstract

[en] A numerical simulation has been constructed to obtain a detailed, quantitative estimate of the electromagnetic fields and currents existing in the Advanced Test Accelerator under conditions of laser guiding. The code treats the secondary electrons by particle simulation and the beam dynamics by a time-dependent envelope model. The simulation gives a fully relativistic description of secondary electrons moving in self-consistent electromagnetic fields. The calculations are made using coordinates t, x, y, z for the electrons and t, ct-z, r for the axisymmetric electromagnetic fields and currents. Code results, showing in particular current enhancement effects, will be given

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11 Oct 1985; 12 p; SDIO/DARPA annual propagation review; Monterey, CA (USA); 24-28 Jun 1985; CONF-8506141--13; Available from NTIS, PC A02/MF A01 as DE86002135

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