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2. Peta-Pascal Pressure Driven by Fast Isochoric Heating with Multi-Picosecond Intense Laser Pulse

Author

Matsuo, Kazuki, Higashi, Naoki, Iwata, Natsumi, Sakata, Shohei, Lee, Seungho, Johzaki, Tomoyuki, Sawada, Hiroshi, Iwasa, Yuki, Law, King Fai Farley, Morita, Hiroki, Ochiai, Yugo, Kojima, Sadaoki, Abe, Yuki, Hata, Masayasu, Sano, Takayoshi, Nagatomo, Hideo, Sunahara, Atsushi, Morace, Alessio, Yogo, Akifumi, Nakai, Mitsuo, Sakagami, Hitoshi, Ozaki, Tetsuo, Yamanoi, Kohei, Norimatsu, Takayoshi, Nakata, Yoshiki, Tokita, Shigeki, Kawanaka, Junji, Shiraga, Hiroyuki, Mima, Kunioki, Azechi, Hiroshi, Kodama, Ryosuke, Arikawa, Yasunobu, Sentoku, Yasuhiko, and Fujioka, Shinsuke

Subjects
Physics - Plasma Physics
Abstract

Fast isochoric laser heating is a scheme to heat a matter with relativistic-intensity ($>$ 10$^{18}$ W/cm$^2$) laser pulse or X-ray free electron laser pulse. The fast isochoric laser heating has been studied for creating efficiently ultra-high-energy-density (UHED) state. We demonstrate an fast isochoric heating of an imploded dense plasma using a multi-picosecond kJ-class petawatt laser with an assistance of externally applied kilo-tesla magnetic fields for guiding fast electrons to the dense plasma.The UHED state with 2.2 Peta-Pascal is achieved experimentally with 4.6 kJ of total laser energy that is one order of magnitude lower than the energy used in the conventional implosion scheme. A two-dimensional particle-in-cell simulation reveals that diffusive heating from a laser-plasma interaction zone to the dense plasma plays an essential role to the efficient creation of the UHED state., Comment: 8 pages, 4 figures, 1 table

Published
2019
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3. Super-ponderomotive electron acceleration in blowout plasma heated by multi-picosecond relativistic intensity laser pulse

Author

Kojima, Sadaoki, Hata, Masayasu, Iwata, Natsumi, Arikawa, Yasunobu, Morace, Alessio, Sakata, Shouhei, Lee, Seungho, Matsuo, Kazuki, Law, King Fai Farley, Morita, Hiroki, Ochiai, Yugo, Yogo, Akifumi, Nagatomo, Hideo, Ozaki, Tetsuo, Johzaki, Tomoyuki, Sunahara, Atsushi, Sakagami, Hitoshi, Zhang, Zhe, Tosaki, Shota, Abe, Yuki, Kawanaka, Junji, Tokita, Shigeki, Nakai, Mitsuo, Nishimura, Hiroaki, Shiraga, Hiroyuki, Azechi, Hiroshi, Sentoku, Yasuhiko, and Fujioka, Shinsuke

Subjects
Physics - Plasma Physics
Abstract

The dependence of the mean kinetic energy of laser-accelerated electrons on the laser intensity, so-called ponderomotive scaling, was derived theoretically with consideration of the motion of a single electron in oscillating laser fields. This scaling explains well the experimental results obtained with high-intensity pulses and durations shorter than a picosecond; however, this scaling is no longer applicable to the multi-picosecond (multi-ps) facility experiments. Here, we experimentally clarified the generation of the super-ponderomotive-relativistic electrons (SP-REs) through multi-ps relativistic laser-plasma interactions using prepulse-free LFEX laser pulses that were realized using a plasma mirror (PM). The SP-REs are produced with direct laser acceleration assisted by the self-generated quasi-static electric field and with loop-injected direct acceleration by the self- generated quasi-static magnetic field, which grow in a blowout plasma heated by a multi-ps laser pulse. Finally, we theoretically derive the threshold pulse duration to boost the acceleration of REs, which provides an important insight into the determination of laser pulse duration at kilojoule- petawatt laser facilities.

Published
2018

4. Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States

Author

Sakata, Shohei, Lee, Seungho, Johzaki, Tomoyuki, Sawada, Hiroshi, Iwasa, Yuki, Morita, Hiroki, Matsuo, Kazuki, Law, King Fai Farley, Yao, Akira, Hata, Masayasu, Sunahara, Atsushi, Kojima, Sadaoki, Abe, Yuki, Kishimoto, Hidetaka, Syuhada, Aneez, Shiroto, Takashi, Morace, Alessio, Yogo, Akifumi, Iwata, Natsumi, Nakai, Mitsuo, Sakagami, Hitoshi, Ozaki, Tetsuo, Yamanoi, Kohei, Norimatsu, Takayoshi, Nakata, Yoshiki, Tokita, Shigeki, Miyanaga, Noriaki, Kawanaka, Junji, Shiraga, Hiroyuki, Mima, Kunioki, Nishimura, Hiroaki, Bailly-Grandvaux, Mathieu, Santos, Joao Jorge, Nagatomo, Hideo, Azechi, Hiroshi, Kodama, Ryosuke, Arikawa, Yasunobu, Sentoku, Yasuhiko, and Fujioka, Shinsuke

Subjects
Physics - Plasma Physics
Abstract

The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of a pre-compressed plasma core with a high-intensity short-pulse laser is an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF ignition sparks. This avoids the ignition quench caused by the hot spark mixing with the surrounding cold fuel, which is the crucial problem of the currently pursued ignition scheme. High-intensity lasers efficiently produce relativistic electron beams (REB). A part of the REB kinetic energy is deposited in the core, and then the heated region becomes the hot spark to trigger the ignition. However, only a small portion of the REB collides with the core because of its large divergence. Here we have demonstrated enhanced laser-to-core energy coupling with the magnetized fast isochoric heating. The method employs a kilo-tesla-level magnetic field that is applied to the transport region from the REB generation point to the core which results in guiding the REB along the magnetic field lines to the core. 7.7 $\pm$ 1.3 % of the maximum coupling was achieved even with a relatively small radial area density core ($\rho R$ $\sim$ 0.1 g/cm$^2$). The guided REB transport was clearly visualized in a pre-compressed core by using Cu-$K_\alpha$ imaging technique. A simplified model coupled with the comprehensive diagnostics yields 6.2\% of the coupling that agrees fairly with the measured coupling. This model also reveals that an ignition-scale areal density core ($\rho R$ $\sim$ 0.4 g/cm$^2$) leads to much higher laser-to-core coupling ($>$ 15%), this is much higher than that achieved by the current scheme.

Published
2017
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5. Kinetic modeling of x-ray laser-driven solid Al plasmas via particle-in-cell simulation

Author

Royle, Ryan, Sentoku, Yasuhiko, Mancini, Roberto C., Paraschiv, Ioana, and Johzaki, Tomoyuki

Subjects
Physics - Plasma Physics
Abstract

Solid-density plasmas driven by intense x-ray free-electron laser (XFEL) radiation are seeded by sources of non-thermal photoelectrons and Auger electrons that ionize and heat the target via collisions. Simulation codes that are commonly used to model such plasmas, such as collisional-radiative (CR) codes, typically assume a Maxwellian distribution and thus instantaneous thermalization of the source electrons. In this study, we present a detailed description and initial applications of a collisional particle-in-cell code, PICLS, that has been extended with a self-consistent radiation transport model and Monte-Carlo models for photoionization and KLL Auger ionization, enabling the fully kinetic simulation of XFEL-driven plasmas. The code is used to simulate two experiments previously performed at the Linac Coherent Light Source investigating XFEL-driven solid-density Al plasmas. It is shown that PICLS-simulated pulse transmissions using the Ecker-Kr\"oll continuum-lowering model agree much better with measurements than do simulations using the Stewart-Pyatt model. Good quantitative agreement is also found between the time-dependent PICLS results and those of analogous simulations by the CR code SCFLY, which was used in the analysis of the experiments to accurately reproduce the observed K{\alpha} emissions and pulse transmissions. Finally, it is shown that the effects of the non-thermal electrons are negligible for the conditions of the particular experiments under investigation., Comment: 12 pages, 11 figures

Published
2017
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9. Integrated Fast Ignition Simulation of Cone-guided Targetwith Three Codes

Author

Sakagami, Hitoshi, Johzaki, Tomoyuki, Nagatomo, Hideo, and Mima, Kunioki

Subjects
Physics - Plasma Physics
Abstract

It was reported that the fuel core was heated up to ~ 0.8 [keV] in the fast ignition experimentswith cone-guided targets, but they could not theoretically explain heating mechanisms and achievement of such high temperature. Thus simulations should play an important role in estimating the schemeperformance, and we must simulate each phenomenon with individual codes and integrate them under the Fast Ignition Integrated Interconnecting code project. In the previous integrated simulations, fast electronsgenerated by the laser-plasma interaction were too hot to efficiently heat the core and we got only 0.096 [keV] temperature rise. Including the density gap at the contact surface between the cone tip and theimploded plasma, the period of core heating became longer and the core was heated by 0.162 [keV], ~69% higher increment compared with ignoring the density gap effect.

Published
2004

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

Author

OZAKI, Tetsuo, ABE, Yuki, ARIKAWA, Yasunobu, SENTOKU, Yasuhiko, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, JITSUNO, Takahisa, NAKATA, Yoshiki, TSUBAKIMOTO, Koji, SUNAHARA, Atsushi, JOHZAKI, Tomoyuki, MIURA, Eisuke, KOMEDA, Osamu, IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, OKIHARA, Shinichiro, ISHII, Katsuhiro, HANAYAMA, Ryohei, MORI, Yoshitaka, KITAGAWA, Yoneyoshi, OZAKI, Tetsuo, ABE, Yuki, ARIKAWA, Yasunobu, SENTOKU, Yasuhiko, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, JITSUNO, Takahisa, NAKATA, Yoshiki, TSUBAKIMOTO, Koji, SUNAHARA, Atsushi, JOHZAKI, Tomoyuki, MIURA, Eisuke, KOMEDA, Osamu, IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, OKIHARA, Shinichiro, ISHII, Katsuhiro, HANAYAMA, Ryohei, MORI, Yoshitaka, and KITAGAWA, Yoneyoshi

Abstract

Polystyrene deuteride shell targets with two holes were imploded by the Gekko XII laser and additionally heated by the LFEX laser in a direct fast ignition experiment. In general, when an ultra-intense laser is injected into a blow-off plasma created by the imploding laser, electrons are generated far from the target core and the energies of electrons increase because the electron acceleration distance has been extended. The blow-off plasma moves not only to the vertical direction but to the lateral direction against the target surface. In a shell target with holes, a lower effective electron temperature can be realized by reducing the inflow of the implosion plasma onto the LFEX path, and high coupling efficiency can be expected. The energies of hot electrons and ions absorbed into the target core were calculated from the energy spectra using three electron energy spectrometers and a neutron time-of-flight measurement system, Mandala. The ions have a large contribution of 74% (electron heating of 4.9 J and ion heating of 14.1 J) to target heating in direct fast ignition., source:T. Ozaki et al 2023 Nucl. Fusion 63 036009, source:https://doi.org/10.1088/1741-4326/acb44d

Published
2023

13. Electromagnetic field growth triggering super-ponderomotive electron acceleration during multi-picosecond laser-plasma interaction

Author

Kojima, Sadaoki, Hata, Masayasu, Iwata, Natsumi, Arikawa, Yasunobu, Morace, Alessio, Sakata, Shohei, Lee, Seungho, Matsuo, Kazuki, Law, King Fai Farley, Morita, Hiroki, Ochiai, Yugo, Yogo, Akifumi, Nagatomo, Hideo, Ozaki, Tetsuo, Johzaki, Tomoyuki, Sunahara, Atsushi, Sakagami, Hitoshi, Zhang, Zhe, Tosaki, Shota, Abe, Yuki, Kawanaka, Junji, Tokita, Shigeki, Nakai, Mitsuo, Nishimura, Hiroaki, Shiraga, Hiroyuki, Azechi, Hiroshi, Sentoku, Yasuhiko, and Fujioka, Shinsuke

Published
2019
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15. 小特集：先進燃料核融合研究の現状と展開 ４．慣性核融合における先進燃料研究

Author

JOHZAKI, Tomoyuki

Subjects
burn-up fraction, non-thermal fusion, ignition condition, inertial fusion, advanced-fuel fusion, DT ignitor
Abstract

慣性核融合における点火条件・燃焼率の簡易モデルによる評価に基づいて，DT 燃料と先進燃料（DD，D3He，p11B）の比較を行い，先進燃料の特徴を概説する．また，近年，特に注目を集めているp11B 燃料については，従来の熱核融合反応だけでなく，非熱的核融合反応に着目したレーザー加速粒子を用いたレーザー実験や，この反応を積極的に用いる点火方式などを紹介する．

Published
2022

17. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

Author

Kojima, Sadaoki, primary, Abe, Yuki, additional, Miura, Eisuke, additional, Ozaki, Tetsuo, additional, Yamanoi, Kohei, additional, Ikeda, Tomokazu, additional, Wang, Yubo, additional, Dun, Jinyuan, additional, Guo, Shuwang, additional, Maekawa, Tamaki, additional, Takizawa, Ryunosuke, additional, Morita, Hiroki, additional, Asano, Shoui, additional, Arikawa, Yasunobu, additional, Sawada, Hiroshi, additional, Ishii, Katsuhiro, additional, Hanayama, Ryohei, additional, Okihara, Shinichiro, additional, Kitagawa, Yoneyoshi, additional, Kajimura, Yasuhiro, additional, Morace, Alessio, additional, Shiraga, Hiroyuki, additional, Shigemori, Keisuke, additional, Sunahara, Atsushi, additional, Iwata, Natsumi, additional, Sano, Takayoshi, additional, Sentoku, Yasuhiko, additional, Johzaki, Tomoyuki, additional, Nishikino, Masaharu, additional, Iwamoto, Akifumi, additional, Nagaoka, Kenichi, additional, Sakagami, Hitoshi, additional, Fujioka, Shinsuke, additional, and Mori, Yoshitaka, additional

Published
2022
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18. Magnetized fast isochoric laser heating for efficient creation of ultra-high-energy-density states

Author

Sakata, Shohei, Lee, Seungho, Morita, Hiroki, Johzaki, Tomoyuki, Sawada, Hiroshi, Iwasa, Yuki, Matsuo, Kazuki, Law, King Fai Farley, Yao, Akira, Hata, Masayasu, Sunahara, Atsushi, Kojima, Sadaoki, Abe, Yuki, Kishimoto, Hidetaka, Syuhada, Aneez, Shiroto, Takashi, Morace, Alessio, Yogo, Akifumi, Iwata, Natsumi, Nakai, Mitsuo, Sakagami, Hitoshi, Ozaki, Tetsuo, Yamanoi, Kohei, Norimatsu, Takayoshi, Nakata, Yoshiki, Tokita, Shigeki, Miyanaga, Noriaki, Kawanaka, Junji, Shiraga, Hiroyuki, Mima, Kunioki, Nishimura, Hiroaki, Bailly-Grandvaux, Mathieu, Santos, João Jorge, Nagatomo, Hideo, Azechi, Hiroshi, Kodama, Ryosuke, Arikawa, Yasunobu, Sentoku, Yasuhiko, and Fujioka, Shinsuke

Published
2018
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19. Hot Electron and Ion Spectra in Axial and Transverse Laser Irradiation in the GXII-LFEX Direct Fast Ignition Experiment

Author

OZAKI, Tetsuo, ABE, Yuki, ARIKAWA, Yasunobu, OKIHARA, Shinichirou, MIURA, Eisuke, SUNAHARA, Atsushi, ISHII, Katsuhiro, HANAYAMA, Ryohei, KOMEDA, Osamu, SENTOKU, Yasuhiko, IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, JOHZAKI, Tomoyuki, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, JITSUNO, Takahisa, NAKATA, Yoshiki, TSUBAKIMOTO, Koji, MORI, Yoshitaka, KITAGAWA, Yoneyoshi, OZAKI, Tetsuo, ABE, Yuki, ARIKAWA, Yasunobu, OKIHARA, Shinichirou, MIURA, Eisuke, SUNAHARA, Atsushi, ISHII, Katsuhiro, HANAYAMA, Ryohei, KOMEDA, Osamu, SENTOKU, Yasuhiko, IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, JOHZAKI, Tomoyuki, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, JITSUNO, Takahisa, NAKATA, Yoshiki, TSUBAKIMOTO, Koji, MORI, Yoshitaka, and KITAGAWA, Yoneyoshi

Abstract

An electron spectrometer was used to measure the electron and ion spectra in two different irradiations of implosion laser to the deuterated spherical shell targets at the direct fast ignition experiments on the Gekko-LFEX facility. In the transverse irradiation against the LFEX laser axis, the low effective hot electron temperature (Teff) and huge neutron yield (Ny) could be obtained although high Teff and low Ny could be observed in the axial irradiation. In the transverse irradiation, the efficient core heating could be obtained because the laser-plasma interaction position is close to the core and the diffusive/ion drag heating may be effective., source:https://doi.org/10.1585/pfr.16.2404076

Published
2022

20. Ten hertz bead pellet injection and laser engagement

Author

MORI, Yoshitaka, ISHII, K., HANAYAMA, R., OKIHARA, S., KITAGAWA, Y., NISHIMURA, Y., KOMEDA, O., HIOKI, T., MOTOHIRO, T., SUNAHARA, Atsushi, SENTOKU, Y., IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, MIURA, E., JOHZAKI, Tomoyuki, MORI, Yoshitaka, ISHII, K., HANAYAMA, R., OKIHARA, S., KITAGAWA, Y., NISHIMURA, Y., KOMEDA, O., HIOKI, T., MOTOHIRO, T., SUNAHARA, Atsushi, SENTOKU, Y., IWAMOTO, Akifumi, SAKAGAMI, Hitoshi, MIURA, E., and JOHZAKI, Tomoyuki

Abstract

source:https://doi.org/10.1088/1741-4326/ac3d69, identifier:0000-0001-7754-9171

Published
2022

21. Super-strong magnetic field-dominated ion beam dynamics in focusing plasma devices

Author

MORACE, A., ABE, Y., HONRUBIA, J.J., IWATA, N., ARIKAWA, Yasunobu, NAKATA, Y., JOHZAKI, Tomoyuki, YOGO, A., SENTOKU, Yasuhiko, MIMA, Kunioki, MA, T., MARISCAL, D., SAKAGAMI, Hitoshi, NORIMATSU, Takayoshi, TSUBAKIMOTO, Koji, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, SHIRAGA, Hiroyuki, SAKAWA, Yohichi, NAKAI, Mitsuo, AZECHI, Hiroshi, FUJIOKA, Shinsuke, KODAMA, Ryosuke, MORACE, A., ABE, Y., HONRUBIA, J.J., IWATA, N., ARIKAWA, Yasunobu, NAKATA, Y., JOHZAKI, Tomoyuki, YOGO, A., SENTOKU, Yasuhiko, MIMA, Kunioki, MA, T., MARISCAL, D., SAKAGAMI, Hitoshi, NORIMATSU, Takayoshi, TSUBAKIMOTO, Koji, KAWANAKA, Junji, TOKITA, Shigeki, MIYANAGA, Noriaki, SHIRAGA, Hiroyuki, SAKAWA, Yohichi, NAKAI, Mitsuo, AZECHI, Hiroshi, FUJIOKA, Shinsuke, and KODAMA, Ryosuke

Abstract

High energy density physics is the field of physics dedicated to the study of matter and plasmas in extreme conditions of temperature, densities and pressures. It encompasses multiple disciplines such as material science, planetary science, laboratory and astrophysical plasma science. For the latter, high energy density states can be accompanied by extreme radiation environments and super-strong magnetic fields. The creation of high energy density states in the laboratory consists in concentrating/depositing large amounts of energy in a reduced mass, typically solid material sample or dense plasma, over a time shorter than the typical timescales of heat conduction and hydrodynamic expansion. Laser-generated, high current–density ion beams constitute an important tool for the creation of high energy density states in the laboratory. Focusing plasma devices, such as cone-targets are necessary in order to focus and direct these intense beams towards the heating sample or dense plasma, while protecting the proton generation foil from the harsh environments typical of an integrated high-power laser experiment. A full understanding of the ion beam dynamics in focusing devices is therefore necessary in order to properly design and interpret the numerous experiments in the field. In this work, we report a detailed investigation of large-scale, kilojoule-class laser-generated ion beam dynamics in focusing devices and we demonstrate that high-brilliance ion beams compress magnetic fields to amplitudes exceeding tens of kilo-Tesla, which in turn play a dominant role in the focusing process, resulting either in a worsening or enhancement of focusing capabilities depending on the target geometry., source:Morace, A., Abe, Y., Honrubia, J.J. et al. Super-strong magnetic field-dominated ion beam dynamics in focusing plasma devices. Sci Rep 12, 6876 (2022). https://doi.org/10.1038/s41598-022-10829-1, source:https://doi.org/10.1038/s41598-022-10829-1

Published
2022

22. Estimation of a Plasma Mirror Reflectivity of LFEX Laser and Relevant Results Using Electron Energy Spectrometers

Author

OZAKI, Tetsuo, MIURA, Eisuke, KOJIMA, Sadaoki, ARIKAWA, Yasunobu, ABE, Yuuki, YAMANOI, Kohei, IKEDA, Tomokazu, ISHII, Katsuhiro, SUNAHARA, Atsushi, JOHZAKI, Tomoyuki, SAWADA, Hiroshi, FUJIOKA, Shinsuke, SAKAGAMI, Hitoshi, KITAGAWA, Yoneyoshi, MORI, Yoshitaka, OZAKI, Tetsuo, MIURA, Eisuke, KOJIMA, Sadaoki, ARIKAWA, Yasunobu, ABE, Yuuki, YAMANOI, Kohei, IKEDA, Tomokazu, ISHII, Katsuhiro, SUNAHARA, Atsushi, JOHZAKI, Tomoyuki, SAWADA, Hiroshi, FUJIOKA, Shinsuke, SAKAGAMI, Hitoshi, KITAGAWA, Yoneyoshi, and MORI, Yoshitaka

Abstract

In the counter-irradiation, which is one of the fast ignition schemes, higher core energy coupling can be expected when there are two hot electron flows in counter directions. Two plasma mirrors were installed for the counter irradiation at about 180 degrees. The hot electron effective temperatures (Teff) were measured by using electron energy spectrometers. Teff vs the laser intensity on a foil target followed Wilkes' scaling law. The energy incident on the target could be calculated by estimating the laser intensity on the target from Teff and estimating the focusing radius from the X-ray pinhole camera image. As a result, the reflectivity could be estimated to be 17 ± 3%., source:https://doi.org/10.1585/pfr.17.2404084

Published
2022

23. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

Author

1000040815156, Kojima, Sadaoki, Abe, Yuki, 1000010358070, Miura, Eisuke, 1000050183033, Ozaki, Tetsuo, 1000030722813, 0000-0003-4492-4099, Yamanoi, Kohei, Ikeda, Tomokazu, Wang, Yubo, Dun, Jinyuan, Guo, Shuwang, Maekawa, Tamaki, Takizawa, Ryunosuke, Morita, Hiroki, Asano, Shoui, 1000090624255, 0000-0002-3142-3060, Arikawa, Yasunobu, Sawada, Hiroshi, 1000030311517, Ishii, Katsuhiro, 1000020418924, Hanayama, Ryohei, Okihara, Shinichiro, 1000040093405, Kitagawa, Yoneyoshi, Kajimura, Yasuhiro, 1000070724326, Morace, Alessio, Shiraga, Hiroyuki, 1000050335395, 0000-0002-3978-8427, Shigemori, Keisuke, Sunahara, Atsushi, 1000070814086, Iwata, Natsumi, 1000080362606, 0000-0001-9106-3856, Sano, Takayoshi, 1000010322653, 0000-0003-2093-7100, Sentoku, Yasuhiko, 1000010397680, Johzaki, Tomoyuki, 1000070370450, Nishikino, Masaharu, 1000000260050, Iwamoto, Akifumi, 1000020353443, Nagaoka, Kenichi, 1000030254452, Sakagami, Hitoshi, 1000040372635, 0000-0001-8406-1772, Fujioka, Shinsuke, Mori, Yoshitaka, 1000040815156, Kojima, Sadaoki, Abe, Yuki, 1000010358070, Miura, Eisuke, 1000050183033, Ozaki, Tetsuo, 1000030722813, 0000-0003-4492-4099, Yamanoi, Kohei, Ikeda, Tomokazu, Wang, Yubo, Dun, Jinyuan, Guo, Shuwang, Maekawa, Tamaki, Takizawa, Ryunosuke, Morita, Hiroki, Asano, Shoui, 1000090624255, 0000-0002-3142-3060, Arikawa, Yasunobu, Sawada, Hiroshi, 1000030311517, Ishii, Katsuhiro, 1000020418924, Hanayama, Ryohei, Okihara, Shinichiro, 1000040093405, Kitagawa, Yoneyoshi, Kajimura, Yasuhiro, 1000070724326, Morace, Alessio, Shiraga, Hiroyuki, 1000050335395, 0000-0002-3978-8427, Shigemori, Keisuke, Sunahara, Atsushi, 1000070814086, Iwata, Natsumi, 1000080362606, 0000-0001-9106-3856, Sano, Takayoshi, 1000010322653, 0000-0003-2093-7100, Sentoku, Yasuhiko, 1000010397680, Johzaki, Tomoyuki, 1000070370450, Nishikino, Masaharu, 1000000260050, Iwamoto, Akifumi, 1000020353443, Nagaoka, Kenichi, 1000030254452, Sakagami, Hitoshi, 1000040372635, 0000-0001-8406-1772, Fujioka, Shinsuke, and Mori, Yoshitaka

Abstract

Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945., A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.

Published
2022

24. Estimation of a Plasma Mirror Reflectivity of LFEX Laser and Relevant Results Using Electron Energy Spectrometers

Author

OZAKI, Tetsuo, primary, MIURA, Eisuke, additional, KOJIMA, Sadaoki, additional, ARIKAWA, Yasunobu, additional, ABE, Yuuki, additional, YAMANOI, Kohei, additional, IKEDA, Tomokazu, additional, ISHII, Katsuhiro, additional, SUNAHARA, Atsushi, additional, JOHZAKI, Tomoyuki, additional, SAWADA, Hiroshi, additional, FUJIOKA, Shinsuke, additional, SAKAGAMI, Hitoshi, additional, KITAGAWA, Yoneyoshi, additional, and MORI, Yoshitaka, additional

Published
2022
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25. Hot Electron and Ion Spectra in Axial and Transverse Laser Irradiation in the GXII-LFEX Direct Fast Ignition Experiment

Author

OZAKI, Tetsuo, primary, ABE, Yuki, additional, ARIKAWA, Yasunobu, additional, OKIHARA, Shinichirou, additional, MIURA, Eisuke, additional, SUNAHARA, Atsushi, additional, ISHII, Katsuhiro, additional, HANAYAMA, Ryohei, additional, KOMEDA, Osamu, additional, SENTOKU, Yasuhiko, additional, IWAMOTO, Akifumi, additional, SAKAGAMI, Hitoshi, additional, JOHZAKI, Tomoyuki, additional, KAWANAKA, Junji, additional, TOKITA, Shigeki, additional, MIYANAGA, Noriaki, additional, JITSUNO, Takahisa, additional, NAKATA, Yoshiki, additional, TSUBAKIMOTO, Koji, additional, MORI, Yoshitaka, additional, and KITAGAWA, Yoneyoshi, additional

Published
2021
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28. Design of a cone target for fast ignition

Author

Sunahara Atsushi, Johzaki Tomoyuki, Nagatomo Hideo, and Mima Kunioki

Subjects
Physics, QC1-999
Abstract

We propose a new type of target for the fast ignition of inertial confinement fusion. Pre-formed plasma inside a cone target can significantly reduce the energy coupling efficiency from the ultra-high intense short-pulse laser to the imploded core plasma. Also, in order to protect the tip of the cone and reduce generation of pre-formed plasma, we propose pointed shaped cone target. In our estimation, the shock traveling time can be delayed 20–30 ps by lower-Z material with larger areal density compared to the conventional gold flat tip. Also, the jet flow can sweep the blow-off plasma from the tip of the cone, and the implosion performance is not drastically affected by the existence of pointed tip. In addition, the self-generated magnetic field is generated along the boundary of cone tip and surrounding CD or DT plasma. This magnetic field can confine fast electrons and focus to the implosion core plasma. Resultant heating efficiency is improved by 30% compared to that with conventional gold flat tip.

Published
2013
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31. Thomson Scattering Measurement of Laser-Produced Plasma in a Magnetic Thrust Chamber

Author

ITADANI, Yutaro, primary, MORITA, Taichi, additional, SAITO, Naoya, additional, EDAMOTO, Masafumi, additional, KOJIMA, Tomihiko, additional, TAKAGI, Mariko, additional, NAGASHIMA, Keisuke, additional, FUJIOKA, Shinsuke, additional, YOGO, Akifumi, additional, NISHIMURA, Hiroaki, additional, SUNAHARA, Atushi, additional, MORI, Yoshitaka, additional, JOHZAKI, Tomoyuki, additional, NAKASHIMA, Hideki, additional, and YAMAMOTO, Naoji, additional

Published
2018
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33. The Behavior of Plasma in a Magnetic Thrust Chamber For Laser Fusion Rocket

Author

Edamoto, Masafumi, Saito, Naoya, Morita, Taichi, Yamamoto, Naoji, Sunahara, Atsushi, Kawashima, Ryosuke, Miura, Satoshi, Nakashima, Hideki, Fujioka, Shinsuke, Yogo, Akifumi, Nishimura, Hiroaki, Mori, Yoshitaka, and Johzaki, Tomoyuki

Abstract

平成27年度宇宙輸送シンポジウム（2016年1月14日-15日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県, Space Transportation Symposium FY2015 (January 14-15, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 資料番号: SA6000050132, レポート番号: STEP-2015-068

Published
2016

34. Control of unsteady laser-produced plasma-flow with a multiple-coil magnetic nozzle

Author

Morita, Taichi, primary, Edamoto, Masafumi, additional, Miura, Satoshi, additional, Sunahara, Atsushi, additional, Saito, Naoya, additional, Itadani, Yutaro, additional, Kojima, Tomihiko, additional, Mori, Yoshitaka, additional, Johzaki, Tomoyuki, additional, Kajimura, Yoshihiro, additional, Fujioka, Shinsuke, additional, Yogo, Akifumi, additional, Nishimura, Hiroaki, additional, Nakashima, Hideki, additional, and Yamamoto, Naoji, additional

Published
2017
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36. Energy distribution of fast electrons accelerated by high intensity laser pulse depending on laser pulse duration

Author

Kojima, Sadaoki, primary, Arikawa, Yasunobu, additional, Morace, Alessio, additional, Hata, Masayasu, additional, Nagatomo, Hideo, additional, Ozaki, Tetsuo, additional, Sakata, Shohei, additional, Lee, Seung Ho, additional, Matsuo, Kazuki, additional, Law, King Fai Farley, additional, Tosaki, Shota, additional, Yogo, Akifumi, additional, Johzaki, Tomoyuki, additional, Sunahara, Atsushi, additional, Sakagami, Hitoshi, additional, Nakai, Mitsuo, additional, Nishimura, Hiroaki, additional, Shiraga, Hiroyuki, additional, Fujioka, Shinsuke, additional, and Azechi, Hiroshi, additional

Published
2016
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38. The Measurement of Plasma Structure in a Magnetic Thrust Chamber

Author

KAWASHIMA, Ryosuke, primary, MORITA, Taichi, additional, YAMAMOTO, Naoji, additional, SAITO, Naoya, additional, FUJIOKA, Shinsuke, additional, NISHIMURA, Hiroaki, additional, MATSUKUMA, Hiraku, additional, SUNAHARA, Atsushi, additional, MORI, Yoshitaka, additional, JOHZAKI, Tomoyuki, additional, and NAKASHIMA, Hideki, additional

Published
2016
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39. Energy Transportation by MeV Hot Electrons in Fast Ignition Plasma Driven with LFEX PW Laser

Author

ZHANG, Zhe, primary, NISHIMURA, Hiroaki, additional, FUJIOKA, Shinsuke, additional, ARIKAWA, Yasunobu, additional, NAKAI, Mitsuo, additional, NAGATOMO, Hideo, additional, SHIRAGA, Hiroyuki, additional, KOJIMA, Sadaoki, additional, MORACE, Alessio, additional, MIYANAGA, Noriaki, additional, KAWANAKA, Junji, additional, NAKATA, Yoshiki, additional, JITSUNO, Takahisa, additional, AZECHI, Hiroshi, additional, OZAKI, Tetsuo, additional, CHEN, Hui, additional, PARK, Jaebum, additional, WILLIAMS, Gerald Jackson, additional, JOHZAKI, Tomoyuki, additional, and SUNAHARA, Atsushi, additional

Published
2014
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40. Kilotesla Magnetic Field due to a Capacitor-Coil Target Driven by High Power Laser

Author

Fujioka, Shinsuke, primary, Zhang, Zhe, additional, Ishihara, Kazuhiro, additional, Shigemori, Keisuke, additional, Hironaka, Youichiro, additional, Johzaki, Tomoyuki, additional, Sunahara, Atsushi, additional, Yamamoto, Naoji, additional, Nakashima, Hideki, additional, Watanabe, Tsuguhiro, additional, Shiraga, Hiroyuki, additional, Nishimura, Hiroaki, additional, and Azechi, Hiroshi, additional

Published
2013
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41. Study on Thermal Responses of Dry Walls in Laser Fusion Reactors

Author

ヤマモト, ケイジ, フルカワ, ヒロユキ, ジョウザキ, トモユキ, コザキ, ヤスジ, ヒロオカ, ヨシヒコ, ウエダ, ヨシオ, ニシカワ, マサヒロ, タナカ, カズオ, Yamamoto, Keiji, Furukawa, Hiroyuki, Johzaki, Tomoyuki, Kozaki, Yasuji, Hirooka, Yoshihiko, Ueda, Yoshio, Nishikawa, Masahiro, Tanaka, Kazuo A., 山本, 敬治, 古河, 裕之, 城﨑, 知至, 神前, 康次, 廣岡, 慶彦, 上田, 良夫, 西川, 雅弘, 田中, 和夫, ヤマモト, ケイジ, フルカワ, ヒロユキ, ジョウザキ, トモユキ, コザキ, ヤスジ, ヒロオカ, ヨシヒコ, ウエダ, ヨシオ, ニシカワ, マサヒロ, タナカ, カズオ, Yamamoto, Keiji, Furukawa, Hiroyuki, Johzaki, Tomoyuki, Kozaki, Yasuji, Hirooka, Yoshihiko, Ueda, Yoshio, Nishikawa, Masahiro, Tanaka, Kazuo A., 山本, 敬治, 古河, 裕之, 城﨑, 知至, 神前, 康次, 廣岡, 慶彦, 上田, 良夫, 西川, 雅弘, and 田中, 和夫

Published
2006

44. Advanced Target Design for the FIREX-I Project

Author

AZECHI, Hiroshi, primary, NAKAI, Mitsuo, additional, HOMMA, Hirofumi, additional, JOHZAKI, Tomoyuki, additional, KOGA, Mayuko, additional, MIMA, Kunioki, additional, MIYANAGA, Noriaki, additional, MURAKAMI, Masakatsu, additional, NAGATOMO, Hideo, additional, NAGAI, Keiji, additional, NAKAMURA, Tatsufumi, additional, NISHIHARA, Katsunobu, additional, NISHIMURA, Hiroaki, additional, NORIMATSU, Takayoshi, additional, SAKAWA, Youichi, additional, SHIGEMORI, Keisuke, additional, SHIRAGA, Hiroyuki, additional, IWAMOTO, Akifumi, additional, MITO, Toshiyuki, additional, SAKAGAMI, Hitoshi, additional, MOTOJIMA, Osamu, additional, KODAMA, Ryosuke, additional, TANAKA, Kazuo A., additional, and SUNAHARA, Atsushi, additional

Published
2009
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47. Ultrahigh-contrast kilojoule-class petawatt LFEX laser using a plasma mirror

Author

Arikawa, Yasunobu, Kojima, Sadaoki, Morace, Alessio, Sakata, Shohei, Gawa, Takayuki, Taguchi, Yuki, Abe, Yuki, Zhang, Zhe, Vaisseau, Xavier, Lee, Seung Ho, Matsuo, Kazuki, Tosaki, Shota, Hata, Masayasu, Kawabata, Koji, Kawakami, Yuhei, Ishida, Masato, Tsuji, Koichi, Matsuo, Satoshi, Morio, Noboru, Kawasaki, Tetsuji, Tokita, Shigeki, Nakata, Yoshiki, Jitsuno, Takahisa, Miyanaga, Noriaki, Kawanaka, Junji, Nagatomo, Hideo, Yogo, Akifumi, Nakai, Mitsuo, Nishimura, Hiroaki, Shiraga, Hiroyuki, Fujioka, Shinsuke, Azechi, Hiroshi, Sunahara, Atsushi, Johzaki, Tomoyuki, Ozaki, Tetsuo, Sakagami, Hitoshi, Sagisaka, Akito, Ogura, Koichi, Pirozhkov, Alexander S., Nishikino, Masaharu, Kondo, Kiminori, Inoue, Shunsuke, Teramoto, Kensuke, Hashida, Masaki, and Sakabe, Shuji

Abstract

Laser pulse contrast exceeding 10^11 was demonstrated on a kilojoule-class petawatt laser for fast ignition experiments (LFEX) laser system [J. Phys. IV France133, 81 (2006)10.1051/jp4:2006133016] by implementing a 2 in. plasma mirror. Laser beams of up to 1.2 kJ striking the plasma mirror with a pulse duration of 1.5 ps were reflected and focused onto a target without significant distortions in the focal spot. Transmitted light from the plasma mirror reveals that it has a high reflectivity 2 ps before the main peak. The estimated laser pulse contrast at the target was 10^11 at 1 ns before the main peak. No preformed plasma was observed with an optical interferometry diagnostics, but in the experiment without a plasma mirror a preplasma was clearly observed. The energetic proton was generated from a 0.1 μm thick CH film showing excellent pulse contrast. This technique constitutes a promising method to enhance the LFEX laser system performance in fast ignition experiments.

Published
2016

48. Reinjection of transmitted laser light into laser-produced plasma for efficient laser ignition

Author

Endo, Takuma, Takenaka, Yuhei, Sako, Yoshiyuki, Honda, Tomohisa, Johzaki, Tomoyuki, and Namba, Shinichi

Abstract

For improving the laser absorption efficiency in laser ignition, the transmitted laser light was returned to the laser-produced plasma by using a corner cube. In the experiments, the transmitted light was reinjected into the plasma at different times. The laser absorption efficiency was found to be substantially improved when the transmitted light was reinjected into the plasma after adequate plasma expansion. Furthermore, through visualization experiments on gas-dynamics phenomena, it was found that the reinjection of the transmitted light affected not only the laser absorption efficiency but also the gas dynamics after breakdown, and thereby the initial flame kernel development.

Published
2016

50. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

Author

Kojima, Sadaoki, Abe, Yuki, Miura, Eisuke, Ozaki, Tetsuo, Yamanoi, Kohei, Ikeda, Tomokazu, Wang, Yubo, Dun, Jinyuan, Guo, Shuwang, Maekawa, Tamaki, Takizawa, Ryunosuke, Morita, Hiroki, Asano, Shoui, Arikawa, Yasunobu, Sawada, Hiroshi, Ishii, Katsuhiro, Hanayama, Ryohei, Okihara, Shinichiro, Kitagawa, Yoneyoshi, Kajimura, Yasuhiro, Morace, Alessio, Shiraga, Hiroyuki, Shigemori, Keisuke, Sunahara, Atsushi, Iwata, Natsumi, Sano, Takayoshi, Sentoku, Yasuhiko, Johzaki, Tomoyuki, Nishikino, Masaharu, Iwamoto, Akifumi, Nagaoka, Kenichi, Sakagami, Hitoshi, Fujioka, Shinsuke, Mori, Yoshitaka, Kojima, Sadaoki, Abe, Yuki, Miura, Eisuke, Ozaki, Tetsuo, Yamanoi, Kohei, Ikeda, Tomokazu, Wang, Yubo, Dun, Jinyuan, Guo, Shuwang, Maekawa, Tamaki, Takizawa, Ryunosuke, Morita, Hiroki, Asano, Shoui, Arikawa, Yasunobu, Sawada, Hiroshi, Ishii, Katsuhiro, Hanayama, Ryohei, Okihara, Shinichiro, Kitagawa, Yoneyoshi, Kajimura, Yasuhiro, Morace, Alessio, Shiraga, Hiroyuki, Shigemori, Keisuke, Sunahara, Atsushi, Iwata, Natsumi, Sano, Takayoshi, Sentoku, Yasuhiko, Johzaki, Tomoyuki, Nishikino, Masaharu, Iwamoto, Akifumi, Nagaoka, Kenichi, Sakagami, Hitoshi, Fujioka, Shinsuke, and Mori, Yoshitaka

Abstract

Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945., A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.

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