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747 results on '"Miyanaga, N."'

2. Laser-ion acceleration via anomalous electron heating

Author

Yogo, A., Mima, K., Iwata, N., Tosaki, S., Morace, A., Arikawa, Y., Fujioka, S., Nishimura, H., Sagisaka, A., Johzaki, T., Matsuo, K., Kamitsukasa, N., Kojima, S., Nagatomo, H., Nakai, M., Shiraga, H., Murakami, M., Tokita, S., Kawanaka, J., Miyanaga, N., Yamanoi, K., Norimatsu, T., Sakagami, H., Bulanov, S. V., Kondo, K., and Azechi, H.

Subjects
Physics - Plasma Physics
Abstract

Using a kilojoule class laser, we demonstrate for the first time that high-contrast picosecond pulses are advantageous for ion acceleration. We show that a laser pulse with optimum duration and a large focal spot accelerates electrons beyond the ponderomotive energy. This anomalous electron heating enables efficient ion acceleration reaching 52 MeV at an intensity of 1.2X10^19 Wcm^-2. The proton energy observed agrees quantitatively with a one-dimensional plasma expansion model newly developed by taking the anomalous heating effect into account. The heating process is confirmed by both measurements with an electron spectrometer and a one-dimensional particle-in-cell simulation. By extending the pulse duration to 6 ps, 5% energy conversion efficiency to protons (50 J out of 1 kJ laser energy) is achieved with an intensity of 10^18-Wcm^-2. The present results are quite encouraging for realizing ion-driven fast ignition and novel ion beamlines., Comment: This paper has been withdrawn by the author to revise the theoretical model on the ion acceleration

Published
2016

4. Hot electron and ion spectra on blow-off plasma free target in GXII-LFEX direct fast ignition experiment

Author

Ozaki, T., primary, Abe, Y., additional, Arikawa, Y., additional, Sentoku, Y., additional, Kawanaka, J., additional, Tokita, S., additional, Miyanaga, N., additional, Jitsuno, T., additional, Nakata, Y., additional, Tsubakimoto, K., additional, Sunahara, A., additional, Jhozaki, T., additional, Miura, E., additional, Komeda, O., additional, Iwamoto, A., additional, Sakagami, H., additional, Okihara, S., additional, Ishii, K., additional, Hanayama, R., additional, Mori, Y., additional, and Kitagawa, Y., additional

Published
2023
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6. Enhancing laser beam performance by interfering intense laser beamlets

Author

Morace, A., Iwata, N., Sentoku, Y., Mima, K., Arikawa, Y., Yogo, A., Andreev, A., Tosaki, S., Vaisseau, X., Abe, Y., Kojima, S., Sakata, S., Hata, M., Lee, S., Matsuo, K., Kamitsukasa, N., Norimatsu, T., Kawanaka, J., Tokita, S., Miyanaga, N., Shiraga, H., Sakawa, Y., Nakai, M., Nishimura, H., Azechi, H., Fujioka, S., and Kodama, R.

Published
2019
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13. Rayleigh Taylor and Laser Imprinting Diagnostics

Author

Azechi, H., Nakai, M., Shigemori, K., Izumi, N., Shiraga, H., Nishikino, M., Sakaiya, T., Fujioka, S., Tamari, Y., Miyanaga, N., Nishimura, H., Stott, Peter E., editor, Wootton, Alan, editor, Gorini, Giuseppe, editor, Sindoni, Elio, editor, and Batani, Dimitri, editor

Published
2002
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14. Integrated experiments of fast ignition targets by Gekko-XII and LFEX lasers

Author

Shiraga, H., Fujioka, S., Nakai, M., Watari, T., Nakamura, H., Arikawa, Y., Hosoda, H., Nagai, T., Koga, M., Kikuchi, H., Ishii, Y., Sogo, T., Shigemori, K., Nishimura, H., Zhang, Z., Tanabe, M., Ohira, S., Fujii, Y., Namimoto, T., Sakawa, Y., Maegawa, O., Ozaki, T., Tanaka, K.A., Habara, H., Iwawaki, T., Shimada, K., Nagatomo, H., Johzaki, T., Sunahara, A., Murakami, M., Sakagami, H., Taguchi, T., Norimatsu, T., Homma, H., Fujimoto, Y., Iwamoto, A., Miyanaga, N., Kawanaka, J., Jitsuno, T., Nakata, Y., Tsubakimoto, K., Sueda, K., Morio, N., Matsuo, S., Kawasaki, T., Sawai, K., Tsuji, K., Murakami, H., Kanabe, T., Kondo, K., Kodama, R., Sarukura, N., Shimizu, T., Mima, K., and Azechi, H.

Published
2012
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16. Present states and future prospect of fast ignition realization experiment (FIREX) with Gekko and LFEX Lasers at ILE

Author

Koga, Mayuko, Arikawa, Y., Azechi, H., Fujimoto, Y., Fujioka, S., Habara, H., Hironaka, Y., Homma, H., Hosoda, H., Jitsuno, T., Johzaki, T., Kawanaka, J., Kodama, R., Mima, K., Miyanaga, N., Murakami, M., Nagatomo, H., Nakai, M., Nakata, Y., Nakamura, H., Nishimura, H., Norimatsu, T., Sakawa, Y., Sarukura, N., Shigemori, K., Shiraga, H., Shimizu, T., Takabe, H., Tanabe, M., Tanaka, K.A., Tanimoto, T., Tsubakimoto, T., Watari, T., Sunahara, A., Isobe, M., Iwamoto, A., Mito, T., Motojima, O., Ozaki, T., Sakagami, H., Taguchi, T., Nakao, Y., Cai, H., Key, M., Norreys, P., and Pasley, J.

Published
2011
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17. Laser Fusion — High Density Compression Experiment and Ignition Program with Gekko XII

Author

Nakai, S., Mima, K., Azechi, H., Miyanaga, N., Nishiguchi, A., Yamanaka, T., Nishihara, K., Tanaka, K. A., Nakai, M., Kodama, R., Katayama, M., Kado, M., Tsukamoto, M., Kato, Y., Takabe, H., Nishimura, H., Shiraga, H., Endo, T., Nakatsuka, M., Sasaki, T., Jitsuno, T., Yoshida, K., Kanabe, T., Nakano, H., Tsubakimoto, K., Yamanaka, M., Naito, K., Norimatsu, T., Takagi, M., Chen, T., Izawa, Y., Yamanaka, C., Miley, George H., editor, and Hora, Heinrich, editor

Published
1992
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19. High Density Compression of Hollow-Shell Target by Gekko XII and Laser Fusion Research at Ile, Osaka University

Author

Nakai, S., Mima, K., Yamanaka, M., Azechi, H., Miyanaga, N., Nishiguchi, A., Nakaishi, H., Chen, Y.-W., Setsuhara, Y., Norreys, P. A., Yamanaka, T., Nishihara, K., Tanaka, K. A., Nakai, M., Kodama, R., Katayama, M., Kato, Y., Takabe, H., Nishimura, H., Shiraga, H., Endo, T., Kondo, K., Nakatsuka, M., Sasaki, T., Jitsuno, T., Yoshida, K., Kanabe, T., Yokotani, A., Norimatsu, T., Takagi, M., Katayama, H., Izawa, Y., Yamanaka, C., Hora, Heinrich, editor, and Miley, George H., editor

Published
1991
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23. Fast heating of ultrahigh-density plasma as a step towards laser fusion ignition

Author

Kodama, R., Norreys, P. A., Mima, K., Dangor, A. E., Evans, R. G., Fujita, H., Kitagawa, Y., Krushelnick, K., Miyakoshi, T., Miyanaga, N., Norimatsu, T., Rose, S. J., Shozaki, T., Shigemori, K., Sunahara, A., Tampo, M., Tanaka, K. A., Toyama, Y., Yamanaka, T., and Zepf, M.

Subjects
Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Author(s): R. Kodama (corresponding author) [1]; P. A. Norreys [2]; K. Mima [1]; A. E. Dangor [3]; R. G. Evans [4]; H. Fujita [1]; Y. Kitagawa [1]; K. Krushelnick [3]; [...]

Published
2001
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25. Implosion and heating experiments of fast ignition targets by Gekko-XII and LFEX lasers

Author

Shiraga H., Fujioka S., Nakai M., Watari T., Nakamura H., Arikawa Y., Hosoda H., Nagai T., Koga M., Kikuchi H., Ishii Y., Sogo T., Shigemori K., Nishimura H., Zhang Z., Tanabe M., Ohira S., Fujii Y., Namimoto T., Sakawa Y., Maegawa O., Ozaki T., Tanaka K.A., Habara H., Iwawaki T., Shimada K., Key M., Norreys P., Pasley J., Nagatomo H., Johzaki T., Sunahara A., Murakami M., Sakagami H., Taguchi T., Norimatsu T., Homma H., Fujimoto Y., Iwamoto A., Miyanaga N., Kawanaka J., Kanabe T., Jitsuno T., Nakata Y., Tsubakimoto K., Sueda K., Kodama R., Kondo K., Morio N., Matsuo S., Kawasaki T., Sawai K., Tsuji K., Murakami H., Sarukura N., Shimizu T., Mima K., and Azechi H.

Subjects
Physics, QC1-999
Abstract

The FIREX-1 project, the goal of which is to demonstrate fuel heating up to 5 keV by fast ignition scheme, has been carried out since 2003 including construction and tuning of LFEX laser and integrated experiments. Implosion and heating experiment of Fast Ignition targets have been performed since 2009 with Gekko-XII and LFEX lasers. A deuterated polystyrene shell target was imploded with the 0.53- μm Gekko-XII, and the 1.053- μm beam of the LFEX laser was injected through a gold cone attached to the shell to generate hot electrons to heat the imploded fuel plasma. Pulse contrast ratio of the LFEX beam was significantly improved. Also a variety of plasma diagnostic instruments were developed to be compatible with harsh environment of intense hard x-rays (γ rays) and electromagnetic pulses due to the intense LFEX beam on the target. Large background signals around the DD neutron signal in time-of-flight record of neutron detector were found to consist of neutrons via (γ,n) reactions and scattered gamma rays. Enhanced neutron yield was confirmed by carefully eliminating such backgrounds. Neutron enhancement up to 3.5 × 107 was observed. Heating efficiency was estimated to be 10–20% assuming a uniform temperature rise model.

Published
2013
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26. Development of high-energy fiber CPA system

Author

Ogino J., Sueda K., Kurita T., Kawashima T., and Miyanaga N.

Subjects
Physics, QC1-999
Abstract

An intense broadband laser system based on a Nd:glass chirped pulse amplifier (CPA) requires a stable front end with good beam quality. To prepare such a front end without using a regenerative amplifier or optical parametric chirped pulse amplification (OPCPA) pumped by the second harmonic of a Nd:YAG laser, we have developed a fiber CPA system using laser diode (LD)-pumped single-mode fibers, large-mode-area (LMA) fibers, and photonic-crystal (rod) fibers. The output pulse energy achieved was 1.2 mJ at a central wavelength of 1053 nm with a spectral width of 10 nm. The power fluctuation was reduced to 0.4% rms at a repetition rate of 10 kHz. The output of this fiber laser is useful as a pump source for a few-cycle noncollinear optical parametric amplifier (NOPA) and a seed for a LD-pumped high-power Nd:glass CPA system.

Published
2013
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27. Three-dimensional imaging of laser-imploded targets using X-ray computed tomography technique

Author

Chen, Y.-W., Miyanaga, N., Yamanaka, M., Nakai, M., Yamanaka, T., and Nakai, S.

Subjects
CT imaging -- Methods, Laser beams -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

An x-ray emission computed tomography technique has been demonstrated to diagnose the laser implosion uniformity of spherical targets. Three-dimensional images of compressed core were reconstructed from five pinhole camera images obtained at different viewing directions by using an iterative algorithm. The uniformity of the heated plasma is estimated from the intensity distribution of the x-ray emitted from the surface of the target.

Published
1997

28. Nomograms including nuclear matrix protein 22 for prediction of disease recurrence and progression in patients with Ta, T1, Tis bladder cancer

Author

SHARIAT, S, SAGALOWSKY, A, ZIPPE, C, LÜDECKE, G, BOMAN, H, SANCHEZ-CARBAYO, M, CASELLA, R, MIAN, C, FRIEDRICH, M G, EISSA, S, AKAZA, H, SAWCZUK, I, SERRETTA, V, HULAND, H, HEDELIN, H, RUPESH, R, MIYANAGA, N, WIANS, F JR, ROEHRBORN, C G, LOTAN, Y, PERROTTE, P, BENAYOUN, S, SULSER, T, GASSER, T C, MARBERGER, M, and KARAKIEWICZ, P

Published
2004

30. Spectrally dispersed amplified spontaneous emission for improving irradiation uniformity into high power Nd:glass laser system

Author

Nakano, H., Tsubakimoto, K., Miyanaga, N., Nakatsuka, M., Kanabe, T., Azechi, H., Jitsuno, T., and Nakai, S.

Subjects
Lasers -- Research, Physics
Abstract

The use of an amplified spontaneous emission (ASE) for enhancing irradiation uniformity into a high power, 12-beam Nd:glass laser system was investigated. The results showed that ASE generated a smooth beam profile and allowed rapid smoothing of speckles to be obtained. In addition, ASE functioned well under high output energy, which reached as high as 1.3 kJ/beam. The reduction rate of the standard deviation of the intensity distribution was in good agreement with numerical results.

Published
1993

31. Partially deuterated potassium dihydrogen phosphate optimized for ultra-broadband optical parametric amplification.

Author

Fujioka, K., Fujimoto, Y., Tsubakimoto, K., Kawanaka, J., Shoji, I., and Miyanaga, N.

Subjects
DEUTERATION, SOLID-state lasers, ULTRA-wideband devices, NONLINEAR optical materials, OPTICAL parametric amplifiers, POTASSIUM dihydrogen phosphate
Abstract

The refractive index of a potassium dihydrogen phosphate (KDP) crystal strongly depends on the deuteration fraction of the crystal. The wavelength dependence of the phase-matching angle in the near-infrared optical parametric process shows convex and concave characteristics for pure KDP and pure deuterated KDP (DKDP), respectively, when pumped by the second harmonic of Nd- or Yb-doped solid state lasers. Using these characteristics, ultra-broadband phase matching can be realized by optimization of the deuteration fraction. The refractive index of DKDP that was grown with a different deuteration fraction (known as partially deuterated KDP or pDKDP) was measured over a wide wavelength range of 0.4-1.5μlm by the minimum deviation method. The wavelength dispersions of the measured refractive indices were fitted using a modified Sellmeier equation, and the deuteration fraction dependence was analyzed using the Lorentz-Lorenz equation. The wavelength-dependent phase-matching angle for an arbitrary deuteration fraction was then calculated for optical parametric amplification with pumping at a wavelength of 526.5 nm. The results revealed that a refractive index database with precision of more than 2×10-5 was necessary for exact evaluation of the phase-matching condition. An ultra-broad gain bandwidth of up to 490 nm will be feasible when using the 68% pDKDP crystal [ABSTRACT FROM AUTHOR]

Published
2015
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35. Plasma mirror implementation on LFEX laser for ion and fast electron fast ignition

Author

Morace, A., primary, Kojima, S., additional, Arikawa, Y., additional, Fujioka, S., additional, Yogo, A., additional, Tosaki, S., additional, Sakata, S., additional, Abe, Y., additional, Lee, S.H., additional, Matsuo, K., additional, Sagisaka, A., additional, Kondo, K., additional, Pirozhkov, A.S., additional, Norimatsu, T., additional, Jitsuno, T., additional, Miyanaga, N., additional, Shiraga, H., additional, Nakai, M., additional, Nishimura, H., additional, and Azechi, H., additional

Published
2017
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36. Characterization of out-of-band radiation and plasma parameters in laser-produced Sn plasmas for extreme ultraviolet lithography light sources.

Author

Namba, S., Fujioka, S., Sakaguchi, H., Nishimura, H., Yasuda, Y., Nagai, K., Miyanaga, N., Izawa, Y., Mima, K., Sato, K., and Takiyama, K.

Subjects
TIN research, INDUSTRIAL lasers, IRRADIATION, ELECTRON distribution, STARK effect, BLACKBODY radiation, LIGHT sources
Abstract

Out-of-band (OOB) radiation, in contrast to the in-band radiation at 13.5 nm in a 2% bandwidth, emitted from dense tin plasmas generated by a laser was investigated for application as an extreme ultraviolet lithography light source. It was found that the continuum spectrum, which overwhelms the atomic and ionic line emissions, is responsible for the intense OOB radiation. The spectral distribution of the continuum emission matches that of blackbody radiation with a temperature of about 10 eV. The OOB radiation can be considerably suppressed by employing a minimum-mass target and short-pulse laser irradiation. Spectroscopic observations were made to examine the spatiotemporal behavior of the plasma immediately after laser irradiation. Prominent line broadening due to the Stark effect in the high-density plasma was observed, from which the variation of the electron density was deduced. The electron density and temperature on the target surface were 1017–1018 cm-3 and a few eV’s, respectively, in the first 200 ns after laser illumination. In addition, the expansion velocities of neutral and singly ionized tin atoms were deduced from time-of-flight transients in the spectral emission. [ABSTRACT FROM AUTHOR]

Published
2008
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40. Measurement of the mass ablation rate for 0.53 μm random phased laser irradiation of spherical targets

Author

Norreys, PA, Miyanaga, N, Nishimura, H, Kondo, K, Azechi, H, Maegawa, O, Nishiguchi, A, Yamanaka, M, Mima, K, Yamanaka, C, and Nakai, S

Abstract

The mass ablation rate has been measured using the 12-beam GEKKO XII glass laser. An X-ray pinhole camera coupled to a streak camera was used to provide both spatial and temporal history of the emission from buried maker layers. The camera was filtered by 0.75 μm of Al to enhance the image of the cool, denser plasma near the ablation front. The targets (diameter approximately 500 μm) were both polymer shells and solid polymer pellets and were overcoated with up to four maker layers sandwiched between CH ablator layers. Laser energies of up to 8 kJ in 1.7 ns were incident on the targets, with absorbed irradiances of up to 4.0 × 1014 W-cm-2. Good agreement has been found between the experiment and a one-dimensional hydrodynamic code in which the heat flow is obtained from the Fokker-Planck equation. The mass data were consistent with the temporal behavior of spectral line emissions observed by a streaked crystal spectrograph. The introduction of random phase plates had no significant influence on the mass ablation rate for imploding targets. The results indicate that a highly uniform drive pressure has been achieved for the GEKKO XII laser.

Published
2016

41. Fast heating with a PW laser as a step to ignition

Author

Kodama, R, Azechi, H, Fujita, H, Habara, H, Izawa, Y, Jitsuno, T, Jozaki, T, Kitagawa, Y, Krushelnick, K, Matsuoka, T, Mima, K, Miyanaga, N, Nagai, K, Negatomo, H, Nakai, M, Nishimura, H, Norimatsu, T, Norreys, P, Shigemori, K, Shiraga, H, Sunahara, A, Tampo, M, Tanaka, K, Toyama, Y, and Tsubakimoto, K

Abstract

We have developed PW(0.5ps/500J) laser system to demonstrate fast heating of imploded core plasmas using a hollow cone shell target. Significant enhancement of thermal neutron yield has been realized with PW-laser heating, confirming that the high heating efficiency is maintained as the short-pulse laser power is substantially increased to near equivalent power to the ignition condition. The efficient heating could be caused by the efficient guiding of heating pulse with the hollow cone and self-organized relativistic electron transport. According to the experimental results, we are now developing a 10kJ-PW laser system to study the ignition-equivalent temperature heating physics.

Published
2016

42. Boosting laser-ion acceleration with multi-picosecond pulses

Author

Yogo, A., primary, Mima, K., additional, Iwata, N., additional, Tosaki, S., additional, Morace, A., additional, Arikawa, Y., additional, Fujioka, S., additional, Johzaki, T., additional, Sentoku, Y., additional, Nishimura, H., additional, Sagisaka, A., additional, Matsuo, K., additional, Kamitsukasa, N., additional, Kojima, S., additional, Nagatomo, H., additional, Nakai, M., additional, Shiraga, H., additional, Murakami, M., additional, Tokita, S., additional, Kawanaka, J., additional, Miyanaga, N., additional, Yamanoi, K., additional, Norimatsu, T., additional, Sakagami, H., additional, Bulanov, S. V., additional, Kondo, K., additional, and Azechi, H., additional

Published
2017
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43. Variability in the performance of Nuclear Matrix Protein 22 in the detection of bladder cancer. Congress of the American Urological Association, AUA ’06 – Atlanta May 20-25, 2006. (Abstr 984). 317;2006

Author

SHARIAT SF, LOTAN Y, SANCHEZ CARBAYO M, ZIPPE CD, LUDECKE G, BOMAN H, SAWCZUK IS, FRIEDRICH MG, CASELLA R, MIAN C, SANAA E, AKAZA H, HEDELIN H, RUPESH R, MIYANAGA N, SAGALOWSKY AI, ROHERBORN CG, WIANS F, SULSER T, TC GASSER, MARBERGER M, KARAKIEWICZ PI, SERRETTA, Vincenzo, SHARIAT SF, LOTAN Y, SANCHEZ-CARBAYO M, ZIPPE CD, LUDECKE G, BOMAN H, SAWCZUK IS, FRIEDRICH MG, CASELLA R, MIAN C, SANAA E, AKAZA H, SERRETTA V, HEDELIN H, RUPESH R, MIYANAGA N, SAGALOWSKY AI, ROHERBORN CG, WIANS F, SULSER T, TC GASSER, MARBERGER M, and KARAKIEWICZ PI

Published
2006

47. Quantitative Kα line spectroscopy for energy transport in ultra-intense laser plasma interaction

Author

Zhang, Z., primary, Nishimura, H., additional, Fujioka, S., additional, Arikawa, Y., additional, Nakai, M., additional, Chen, H., additional, Park, J., additional, Williams, G. J., additional, Ozaki, T., additional, Shiraga, H., additional, Kojima, S., additional, Johzaki, T., additional, Sunahara, A., additional, Miyanaga, N., additional, Kawanaka, J., additional, Nakata, Y., additional, Jitsuno, T., additional, and Azechi, H., additional

Published
2016
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48. Progress Towards a Laser Produced Relativistic Electron-Positron Pair Plasma

Author

Chen, Hui, primary, Bonlie, J., additional, Cauble, R., additional, Fiuza, F., additional, Goldstein, W., additional, Hazi, A., additional, Keane, C., additional, Link, A., additional, Marley, E., additional, Nagel, S. R., additional, Park, J., additional, Shepherd, R., additional, Williams, G. J., additional, Meyerhofer, D. D., additional, Fiksel, G., additional, Barnak, D., additional, Chang, P. Y., additional, Nakai, M., additional, Arikawa, Y., additional, Azechi, H., additional, Fujioka, S., additional, Kojima, S., additional, Miyanaga, N., additional, Morita, T., additional, Nagai, T., additional, Nishimura, H., additional, Ozaki, T., additional, Sakawa, Y., additional, Takabe, H., additional, Zhang, Z., additional, Kerr, S., additional, Fedosejevs, R., additional, Sentoku, Y., additional, Hill, M. P., additional, Hoarty, D. J., additional, Hobbs, L. M. R., additional, and James, S. F., additional

Published
2016
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