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Grote, D.P.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1994
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1994
AbstractAbstract
[en] Heavy ion fusion requires injection, transport and acceleration of high current beams. Detailed simulation of such beams requires fully self-consistent space charge fields and three dimensions. WARP3D, developed for this purpose, is a particle-in-cell plasma simulation code optimized to work within the framework of an accelerator's lattice of accelerating, focusing, and bending elements. The code has been used to study several test problems and for simulations and design of experiments. Two applications are drift compression experiments on the MBE-4 facility at LBL and design of the electrostatic quadrupole injector for the proposed ILSE facility. With aggressive drift compression on MBE-4, anomalous emittance growth was observed. Simulations carried out to examine possible causes showed that essentially all the emittance growth is result of external forces on the beam and not of internal beam space-charge fields. Dominant external forces are the dodecapole component of focusing fields, the image forces on the surrounding pipe and conductors, and the octopole fields that result from the structure of the quadrupole focusing elements. Goal of the design of the electrostatic quadrupole injector is to produce a beam of as low emittance as possible. The simulations show that the dominant effects that increase the emittance are the nonlinear octopole fields and the energy effect (fields in the axial direction that are off-axis). Injectors were designed that minimized the beam envelope in order to reduce the effect of the nonlinear fields. Alterations to the quadrupole structure that reduce the nonlinear fields further were examined. Comparisons were done with a scaled experiment resulted in very good agreement
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1 Nov 1994; 129 p; CONTRACT W-7405-ENG-48; Also available from OSTI as DE96000393; NTIS; US Govt. Printing Office Dep; Thesis (Ph.D.).
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Report
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Thesis/Dissertation
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Grote, D.P.; Sharp, W.M.
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director. Office of Science. Office of Fusion Energy Sciences. DE-AC03-76SF00098, Lawrence Livermore National Laboratory Contract W-7405-ENG-48 (United States)2004
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director. Office of Science. Office of Fusion Energy Sciences. DE-AC03-76SF00098, Lawrence Livermore National Laboratory Contract W-7405-ENG-48 (United States)2004
AbstractAbstract
[en] Simulation of designs of an Integrated Beam Experiment (IBX) class accelerator have been carried out. These simulations are an important tool for validating such designs. Issues such as envelope mismatch and emittance growth can be examined in a self-consistent manner, including the details of injection, accelerator transitions, long-term transport, and longitudinal compression. The simulations are three-dimensional and time-dependent, and begin at the source. They continue up through the end of the acceleration region, at which point the data is passed on to a separate simulation of the drift compression. Results are be presented
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11 Jun 2004; 10 p; 15. International Symposium on Heavy Ion Inertial Fusion; Princeton, NJ (United States); 7-11 Jun 2004; HIFAN--1356; AC03-76SF00098; Also available from OSTI as DE00841055; PURL: https://www.osti.gov/servlets/purl/841055-dHTOT6/native/
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Report
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Conference
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Friedman, A.; Grote, D.P.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE Assistant Secretary for Defense Programs, Washington, DC (United States)1996
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE Assistant Secretary for Defense Programs, Washington, DC (United States)1996
AbstractAbstract
[en] Under conditions which arise commonly in space-charge-dominated beam applications, the applied focusing, bending, and accelerating fields vary rapidly with axial position, while the self-fields (which are, on average, comparable in strength to the applied fields) vary smoothly. In such cases it is desirable to employ timesteps which advance the particles over distances greater than the characteristic scales over which the applied fields vary. Several related concepts are potentially applicable: sub-cycling of the particle advance relative to the field solution, a higher-order time-advance algorithm, force-averaging by integration along approximate orbits, and orbit-averaging. We report on our investigations into the utility of such techniques for systems typical of those encountered in accelerator studies for heavy-ion beam-driven inertial fusion
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Oct 1996; 10 p; CAP '96: the 1996 computational accelerator physics conference; Williamsburg, VA (United States); 24-27 Sep 1996; CONF-9609256--9; CONTRACT W-7405-ENG-48; Available from OSTI as DE97051379; NTIS; US Govt. Printing Office Dep
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Report
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Conference
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Sharp, W.M.; Grote, D.P.
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: Office of Science. Fusion Energy Sciences (United States)2002
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: Office of Science. Fusion Energy Sciences (United States)2002
AbstractAbstract
No abstract available
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Source
LBNL--49652; HIFAN--1144; AC--03-76SF00098; Journal Publication Date: September 2002
Record Type
Journal Article
Journal
Physical Review Special Topics. Accelerators and Beams; ISSN 1098-4402;
; v. 509(9); [10 p.]

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INIS IssueINIS Issue
Sharp, W.M.; Grote, D.P.
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director, Office of Science (United States)2002
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director, Office of Science (United States)2002
AbstractAbstract
[en] Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d
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1 May 2002; 10 p; IEEE Particle Accelerator Conference (PAC 99); New York, NY (United States); 29 Mar - 2 Apr 1999; HIFAN--1166; AC03-76SF00098; Also available from OSTI as DE00822248; PURL: https://www.osti.gov/servlets/purl/822248-UnjHIa/native/
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Report
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Conference
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INIS IssueINIS Issue
Grote, D.P.; Sharp, W.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE Office of Energy Research (ER) (United States)1999
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE Office of Energy Research (ER) (United States)1999
AbstractAbstract
[en] The recent development of miniature inductive adders has made it feasible to design programmable, high-repetition-rate pulsers with a substantially higher voltage than is possible using a conventional field-effect transistor architecture. Prototype pulsers using the new technology are being developed as part of a series of experiments at LLNL to test the concept of a recirculating induction accelerator. Preliminary numerical work is reported here to determine what effects the higher-voltage pulsers would have on the beam quality of the LLNL small recirculator
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Source
1 Jun 1999; 634 Kilobytes; 1999 Particle Accelerator Conference; New York, NY (United States); 29 Mar - 2 Apr 1999; AT--5015031; W-7405-ENG-48; Available from PURL: https://www.osti.gov/servlets/purl/9651-pNf52r/native/
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Report
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Conference
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Reference NumberReference Number
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INIS IssueINIS Issue
Sharp, W.M.; Callahan, D.A.; Grote, D.P.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1996
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1996
AbstractAbstract
[en] Successful transport of induction-driven beams for heavy-ion fusion requires careful control of the longitudinal space charge. The usual control technique is the periodic application of time-varying longitudinal electric fields, called 'ears', that on the average, balance the space-charge field. this technique is illustrated using a fluid/envelope code CIRCE, and the sensitivity of the method to errors in these ear fields is illustrated. The possibility that periodic ear fields also excite the longitudinal instability is examined
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5 Jan 1996; 12 p; 8. International Committee for Future Accelerators (ICFA) advanced beam dynamics workshop on space charge dominated beams and applications of high brightness beams; Bloomington, IN (United States); 11-13 Oct 1995; CONF-9510263--11; CONTRACT W-7405-ENG-48; Also available from OSTI as DE96009090; NTIS; US Govt. Printing Office Dep
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Report
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Conference
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INIS IssueINIS Issue
Sharp, W.M.; Friedman, A.; Grote, D.P.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1995
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1995
AbstractAbstract
[en] A new analytic model is presented that accurately estimates the radially averaged axial component of the space-charge field of an axisymmetric heavy-ion beam in a cylindrical beam pipe. The model recovers details of the field near the beam ends that are overlooked by simpler models, and the results compare well to exact solutions of Poisson's equation. Field values are shown for several simple beam profiles and are compared with values obtained from simpler models. The model has been implemented in the fluid/envelope code CIRCE and used to study longitudinal confinement in beams with a variety of axial profiles. The effects of errors in the longitudinal-control fields are presented
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Secondary Subject
Source
1 Sep 1995; 11 p; International symposium on heavy ion inertial fusion; Princeton, NJ (United States); 6-9 Sep 1995; CONF-9509149--2; CONTRACT W-7405-ENG-48; Also available from OSTI as DE96000753; NTIS; US Govt. Printing Office Dep
Record Type
Report
Literature Type
Conference; Numerical Data
Report Number
Country of publication
Reference NumberReference Number
INIS VolumeINIS Volume
INIS IssueINIS Issue
Sharp, W.M.; Friedman, A.; Grote, D.P.
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1995
Lawrence Livermore National Lab., CA (United States). Funding organisation: USDOE, Washington, DC (United States)1995
AbstractAbstract
[en] A new analytic model is presented that accurately estimates the radially averaged axial component of the space-charge field of an axisymmetric heavy-ion beam in a cylindrical beam pipe. The model recovers details of the field near the beam ends that are overlooked by simpler models, and the results compare well to exact solutions of Poisson's equation. Field values are shown for several simple beam profiles and are compared with values obtained from simpler models. The model has been implemented in the fluid/envelope code CIRCE and used to study longitudinal confinement in beams with a variety of axial profiles. The effects of errors in the longitudinal-control fields are presented
Primary Subject
Secondary Subject
Source
27 Dec 1995; 11 p; 8. ICFA advanced beam dynamics workshop on space charge dominated beams and applications of high brightness beams; Bloomington, IN (United States); 11-13 Oct 1995; CONF-9510263--3; CONTRACT W-7405-ENG-48; Also available from OSTI as DE96005373; NTIS; US Govt. Printing Office Dep
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Report
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Conference
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INIS VolumeINIS Volume
INIS IssueINIS Issue
Grote, D.P.; Kwan, J.; Westenskow, G.
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director. Office of Science. Office of Fusion Energy Sciences, Lawrence Livermore National Laboratory Contract W-7405-ENG-48 (United States)2003
Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Funding organisation: USDOE Director. Office of Science. Office of Fusion Energy Sciences, Lawrence Livermore National Laboratory Contract W-7405-ENG-48 (United States)2003
AbstractAbstract
[en] In Heavy-Fusion and in other applications, there is a need for high brightness sources with both high current and low emittance. The traditional design with a single monolithic source, while very successful, has significant constraints on it when going to higher currents. With the Child-Langmuir current-density limit, geometric aberration limits, and voltage breakdown limits, the area of the source becomes a high power of the current, A ∼ I8/3. We are examining a multi-beamlet source, avoiding the constraints by having many beamlets each with low current and small area. The beamlets are created and initially accelerated separately and then merged to form a single beam. This design offers a number of potential advantages over a monolithic source, such as a smaller transverse footprint, more control over the shaping and aiming of the beam, and more flexibility in the choice of ion sources. A potential drawback, however, is the emittance that results from the merging of the beamlets. We have designed injectors using simulation that have acceptably low emittance and are beginning to examine them experimentally
Primary Subject
Source
1 Feb 2003; 3 p; Particle Accelerator Conference PAC; Chicago, IL (United States); 10 Jan 2003; HIFAN--1302; AC--03-76SF00098; Also available from OSTI as DE00838046; PURL: https://www.osti.gov/servlets/purl/838046-kyWql9/native/
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