6 results on '"Someya, T."'
Search Results
2. Robust heavy-ion-beam illumination against a direct-drive-pellet displacement in inertial confinement fusion.
- Author
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Miyazawa, K., Ogoyski, A. I., Kawata, S., Someya, T., and Kikuchi, T.
- Subjects
ION bombardment ,LIGHTING ,INERTIAL confinement fusion ,FUEL ,COMPUTER simulation ,PHYSICAL & theoretical chemistry - Abstract
Nonuniformity of heavy-ion-beam (HIB) illumination is one of key issues in the HIB inertial confinement fusion (ICF): implosion symmetry should be less than a few percent in order to compress a fuel sufficiently and release fusion energy effectively. In this paper a new HIB illumination scheme is presented in order to realize a robust illumination scheme against a displacement of a direct-driven fuel pellet in an ICF reactor. It is known that the HIB illumination nonuniformity is sensitive to a little pellet displacement from a reactor chamber center; a pellet displacement of only 50–100 μm was tolerable in the conventional HIB illumination schemes. In this paper by three-dimensional computer simulations a new robust HIB illumination scheme was found, in which a 200–300 μm displacement is allowed. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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3. Heavy ion beam irradiation non-uniformity in inertial fusion
- Author
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Ogoyski, A.I., Someya, T., Sasaki, T., and Kawata, S.
- Subjects
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HEAVY ions , *BEAM optics , *IRRADIATION - Abstract
A non-uniformity of heavy ion beam irradiation onto a direct-driven fuel pellet in heavy ion fusion (HIF) is studied numerically. The energy deposition non-uniformity is investigated by several beam irradiation systems. The results demonstrate for the first time in HIF that the deposition non-uniformity can be reduced to low values, for example, less than 2% for a 32-beam irradiation system. [Copyright &y& Elsevier]
- Published
- 2003
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4. Code OK1—Simulation of multi-beam irradiation on a spherical target in heavy ion fusion
- Author
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Ogoyski, A.I., Someya, T., and Kawata, S.
- Subjects
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HEAVY ion fusion reactions , *WOOD pellets , *IRRADIATION - Abstract
Code OK1 is a fast and precise three-dimensional computer program designed for simulations of heavy ion beam (HIB) irradiation on a direct-driven spherical fuel pellet in heavy ion fusion (HIF). OK1 provides computational capabilities of a three-dimensional energy deposition profile on a spherical fuel pellet and the HIB irradiation non-uniformity evaluation, which are valuables for optimizations of the beam parameters and the fuel pellet structure, as well for further HIF experiment design. The code is open and complete, and can be easily modified or adapted for users'' purposes in this field.: Program summaryTitle of program: OK1Catalogue identifier: ADSTProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSTProgram obtainable from: CPC Program Library, Queen''s University of Belfast, N. IrelandComputer: PC (Pentium 4,
∼1 GHz or more recommended)Operating system: Windows or UNIXProgram language used: C++Memory required to execute with typical data: 911 MBNo. of bits in a word: 32No. of processors used: 1 CPUHas the code been vectorized or parallelized: NoNo. of bytes in distributed program, including test data: 16 557Distribution format: tar gzip fileKeywords: Heavy ion beam, inertial confinement fusion, energy deposition, fuel pelletNature of physical problem: Nuclear fusion energy may have attractive features as one of our human energy resources. In this paper we focus on heavy ion inertial confinement fusion (HIF). Due to a favorable energy deposition behavior of heavy ions in matter [J.J. Barnard et al., UCRL-LR-108095, 1991; C. Deutsch et al., J. Plasma Fusion Res. 77 (2001) 33; T. Someya et al., Fusion Sci. Tech. (2003), submitted] it is expected that heavy ion beam (HIB) would be one of energy driver candidates to operate a future inertial confinement fusion power plant. For a successful fuel ignition and fusion energy release, a stringent requirement is imposed on the HIB irradiation non-uniformity, which should be less than a few percent [T. Someya et al., Fusion Sci. Tech. (2003), submitted; M.H. Emery et al., Phys. Rev. Lett. 48 (1982) 253; S. Kawata et al., J. Phys. Soc. Jpn. 53 (1984) 3416]. In order to meet this requirement we need to evaluate the non-uniformity of a realistic HIB irradiation and energy deposition pattern. The HIB irradiation and non-uniformity evaluations are sophisticated and difficult to calculate analytically. Based on our code one can numerically obtain a three-dimensional profile of energy deposition and evaluate the HIB irradiation non-uniformity onto a spherical target for a specific HIB parameter value set in HIF.Method of solution: OK1 code is based on the stopping power of ions in matter [J.J. Barnard et al., UCRL-LR-108095, 1991; C. Deutsch et al., J. Plasma Fusion Res. 77 (2001) 33; T. Someya et al., Fusion Sci. Tech. (2003), submitted; M.H. Emery et al., Phys. Rev. Lett. 48 (1982) 253; S. Kawata et al., J. Phys. Soc. Jpn. 53 (1984) 3416; T. Mehlhorn, SAND80-0038, 1980; H.H. Andersen, J.F. Ziegler, Pergamon Press, 1977, p. 3]. The code simulates a multi-beam irradiation, obtains the 3D energy deposition profile of the fuel pellet and evaluates the deposition non-uniformity.Restrictions on the complexity of the problem: NoTypical running time: The execution time depends on the number of beams in the simulated irradiation and its characteristics (beam radius on the pellet surface, beam subdivision, projectile particle energy and so on). In almost of the practical running tests performed, the typical running time for one beam deposition is less than 2 s on a PC with a CPU of Pentium 4, 2.2 GHz (e.g., in Test 2 when the number of beams is 600, the running time is about 18 minutes).Unusual features of the program: No [Copyright &y& Elsevier]- Published
- 2004
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5. Code OK2—A simulation code of ion-beam illumination on an arbitrary shape and structure target
- Author
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Ogoyski, A.I., Kawata, S., and Someya, T.
- Subjects
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COMPUTER simulation , *SIMULATION methods & models , *MEDICAL care , *COMPUTER operating systems - Abstract
For computer simulations on heavy ion beam (HIB) irradiation on a spherical fuel pellet in heavy ion fusion (HIF) the code OK1 was developed and presented in [Comput. Phys. Commun. 157 (2004) 160–172]. The new code OK2 is a modified upgraded computer program for more common purposes in research fields of medical treatment, material processing as well as HIF. OK2 provides computational capabilities of a three-dimensional ion beam energy deposition on a target with an arbitrary shape and structure.Program summary: Title of program: OK2Catalogue identifier: ADTZOther versions of this program [1]: Title of the program: OK1 Catalogue identifier: ADSTProgram summary URL: Program obtainable from: CPC Program Library, Queen''s University of Belfast, N. IrelandComputer: PC (Pentium 4, ∼1 GHz or more recommended)Operating system: Windows or UNIXProgram language used: C++Memory required to execute with typical data: 2048 MBNo. of bits in a word: 32No. of processors used: 1CPUHas the code been vectorized or parallelized: NoNo. of bytes in distributed program, including test data: 17 334No of lines in distributed program, including test date: 1487Distribution format: tar gzip fileNature of physical problem: In research areas of HIF (Heavy Ion Beam Inertial Fusion) energy [1–4] and medical material sciences [5], ion energy deposition profiles need to be evaluated and calculated precisely. Due to a favorable energy deposition behavior of ions in matter [1–4] it is expected that ion beams would be one of preferable candidates in various fields including HIF and material processing. Especially in HIF for a successful fuel ignition and a sufficient fusion energy release, a stringent requirement is imposed on the HIB irradiation non-uniformity, which should be less than a few percent [4,6,7]. In order to meet this requirement we need to evaluate the uniformity of a realistic HIB irradiation and energy deposition pattern. The HIB irradiation and non-uniformity evaluations are sophisticated and difficult to calculate analytically. Based on our code one can numerically obtain a three-dimensional profile of energy deposition onto an arbitrary shape and structure target.Method of solution: OK2 code works on the base of OK1 [1–9]. The code simulates a multi-beam illumination on a target with arbitrary shape and structure, and obtains the 3D energy deposition profile.Restrictions on the complexity of the problem: NoneTypical running time: The execution time depends on the pellet mesh number and the number of beams in the simulated illumination as well as on the beam characteristics (beam radius on the pellet surface, beam subdivision, projectile particle energy and so on). In almost of the practical running tests performed, the typical running time for one beam deposition is about 40 s on a PC with a CPU of Pentium 4, 2.4 GHz.Unusual features of the program: NoneReferences: [1] A.I. Ogoyski, et al., Code OK1—Simulation of multi-beam irradiation on a spherical target in heavy ion fusion, Comput. Phys. Commun. 157 (2004) 160–172. [2] J.J. Barnard, et al., Lawrence Livermore National Laboratory Research Report, UCRL-LR-108095 (1991). [3] C. Deutsch, et al., J. Plasma and Fusion Res. 77 (2001) 33. [4] T. Someya, et al., Fusion Science Tech. 43 (2003) 282–289. [5] S.V. Bulanov, et al., Phys. Lett. A 299 (2002) 240–247. [6] M.H. Emery, et al., Phys. Rev. Lett. 48 (1982) 253. [7] S. Kawata, et al., J. Phys. Soc. Japan 53 (1984) 3416. [8] T. Mehlhorn, Sandia Report, SAND80-0038 (1980). [9] H.H. Andersen, J.F. Ziegler, The Stopping and Ranges of Ions in Matter, vol. 3, Pergamon Press, Elmsford, NY, 1977. [Copyright &y& Elsevier]
- Published
- 2004
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6. Direct–indirect mixed implosion mode in heavy ion inertial fusion
- Author
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Kawata, S., Miyazawa, K., Kikuchi, T., and Someya, T.
- Subjects
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PHYSICAL & theoretical chemistry , *ION bombardment , *CONTROLLED fusion , *FUSION reactors - Abstract
Abstract: In order to realize an effective implosion, beam illumination non-uniformity on a fuel target must be suppressed less than a few percent. In this study, a direct–indirect mixture implosion mode is proposed and discussed in heavy ion beam (HIB) inertial confinement fusion (HIF) in order to release sufficient fusion energy in a robust manner. On the other hand, the HIB illumination non-uniformity depends strongly on a target displacement dz from the center of a fusion reactor chamber. In a direct-driven implosion mode, dz of ∼20μm was tolerable, and in an indirect-implosion mode, dz of ∼100μm was allowable. In the direct–indirect mixture mode target, a low-density foam layer is inserted, and the radiation energy is confined in the foam layer. In the foam layer, the radiation transport is expected to smooth the HIB illumination non-uniformity in the lateral direction. Two-dimensional implosion simulations are performed, and show that the HIB illumination non-uniformity is well smoothed in the direct–indirect mixture target. Our simulation results present that a large pellet displacement of approximately a few hundred microns is allowed in order to obtain a sufficient fusion energy output in HIF. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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