Explanipedia

Physics of matter and Rayleigh–Taylor hydro mixing in high-energy-density plasmas Open

Snezhana I. Abarzhi, H. Azechi, Kurt C. Williams · 2025

This work considers the available experimental data on Rayleigh–Taylor mixing in high-energy-density plasmas. The experiments at the SACLA facility use the experimental platform coupling a high-power optical laser, an x-ray free-electron l…

Enhancement of J x B electron acceleration with the micro-structured target and picosecond high-contrast relativistic-intensity laser pulse Open

Yuga Karaki, Hiroki Matsubara, Rinya Akematsu, Ryou Oomura, H. Azechi , et al. · 2025

Efficient generation of multi-hundred-keV electrons is essential for isochoric heating and can influence ion acceleration. We investigated electron acceleration from copper-oleate foil targets, either planar or coated with a gold mesh stru…

Effect of irradiation uniformity on quasi-isentropic shock compression of solid spheres Open

Ryunosuke Takizawa, Sakagami Hitoshi, Hideo Nagatomo, Yasunobu Arikawa, Hiroki Morita , et al. · 2024

In inertial confinement fusion using central ignition, the ignition hot spot is generated through self-heating during fuel compression. In contrast, fast ignition creates the hot spot through external heating. This difference allows the fa…

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

A. Morace, Y. Abe, J. J. Honrubia, Natsumi Iwata, Yasunobu Arikawa , et al. · 2022

Petapascal Pressure Driven by Fast Isochoric Heating with a Multipicosecond Intense Laser Pulse Open

Kazuki Matsuo, Naoki Higashi, Natsumi Iwata, Shohei Sakata, Seungho Lee , et al. · 2020

Fast isochoric laser heating is a scheme to heat matter with a relativistic intensity (>10^{18} W/cm^{2}) laser pulse for producing an ultrahigh-energy-density (UHED) state. We have demonstrated an efficient fast isochoric heating of a com…

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

Sadaoki Kojima, M. Hata, Natsumi Iwata, Yasunobu Arikawa, A. Morace , et al. · 2019

The dependence of the mean kinetic energy of laser-accelerated relativistic electrons (REs) on the laser intensity, so-called ponderomotive scaling, explains well the experimental results to date; however, this scaling is no longer applica…

Enhancing laser beam performance by interfering intense laser beamlets Open

A. Morace, Natsumi Iwata, Y. Sentoku, K. Mima, Yasunobu Arikawa , et al. · 2019

Increasing the laser energy absorption into energetic particle beams represents a longstanding quest in intense laser-plasma physics. During the interaction with matter, part of the laser energy is converted into relativistic electron beam…

Magnetized fast isochoric laser heating for efficient creation of ultra-high-energy-density states Open

Shohei Sakata, Seungho Lee, Hiroki Morita, T. Johzaki, Hiroshi Sawada , et al. · 2018

Two-Dimensional Computation of Pulsed Magnetic Field Diffusion Dynamics in Gold Cone with Consideration of Inductive Heating and Temperature Dependence of Electrical Conductivity Open

Hiroki Morita, Atsushi Sunahara, Yasunobu Arikawa, H. Azechi, Shinsuke Fujioka · 2018

Application of an external kilo-tesla-level magnetic field, which can be generated using high-intensity laser, to a target is a promising scheme to reduce spray angle of a laser-driven relativistic electron beam (REB) for enhancing the iso…

3 × 10<sup>8 </sup>D-D Neutron Generation by High-Intensity Laser Irradiation onto the Inner Surface of Spherical CD Shells Open

N. Satoh, T. Watari, Katsunobu Nishihara, Koji Matsukado, Ryo Yoshimura , et al. · 2018

3 × 108 deuterium-deuterium (D-D) neutron generation per pulse was achieved with one-sided laser irradiation through an inlet hole of a deuterated polystyrene shell and a laser intensity of (2-3) × 1016 W/cm2. X-ray pinhole camera images d…

Erratum: “Efficient and Repetitive Neutron Generation by Double-Laser-Pulse Driven Photonuclear Reaction” [Plasma Fusion Res. 13, 2404009 (2018)] Open

Yasunobu Arikawa, Yusuke Kato, Y. Abe, Shuto MATSUBARA, H. Kishimoto , et al. · 2018

Super-ponderomotive electron acceleration in blowout plasma heated by multi-picosecond relativistic intensity laser pulse Open

Sadaoki Kojima, M. Hata, Natsumi Iwata, Yasunobu Arikawa, A. Morace , et al. · 2018

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. …

Effect of equation of state on laser imprinting by comparing diamond and polystyrene foils Open

Hiroki Kato, K. Shigemori, Hideo Nagatomo, M. Nakai, T. Sakaiya , et al. · 2018

We present herein a comprehensive study of how the equation of state affects laser imprinting by nonuniform laser irradiation of an inertial fusion target. It has been suggested that a stiffer and denser material would reduce laser imprint…

Efficient and Repetitive Neutron Generation by Double-Laser-Pulse Driven Photonuclear Reaction Open

Yasunobu Arikawa, Yusuke Kato, Y. Abe, Shuto MATSUBARA, H. Kishimoto , et al. · 2018

A short and high-intensity neutron pulse can be produced efficiently by using photonuclear reactions caused by Bremsstrahlung hard X-rays in a lase-irradiated high-Z target.The efficient and repetitive neutron generation was demonstrated w…

Evaluation of laser-driven ion energies for fusion fast-ignition research Open

S. Tosaki, Akifumi Yogo, K. Koga, K. Okamoto, Satoru Shokita , et al. · 2017

We investigate laser-driven ion acceleration using kJ-class picosecond (ps) laser pulses as a fundamental study for ion-assisted fusion fast ignition, using a newly developed Thomson-parabola ion spectrometer (TPIS). The TPIS has a space- …

Fast ion acceleration in a foil plasma heated by a multi-picosecond high intensity laser Open

Natsumi Iwata, K. Mima, Y. Sentoku, Akifumi Yogo, Hideo Nagatomo , et al. · 2017

We study the one-dimensional expansion of a thin foil plasma irradiated by a high intensity laser with multi-picosecond (ps) pulse durations by using particle-in-cell simulation. Electrons are found to recirculate around the expanding plas…

Boosting laser-ion acceleration with multi-picosecond pulses Open

Akifumi Yogo, K. Mima, Natsumi Iwata, S. Tosaki, A. Morace , et al. · 2017

Optical transmittance investigation of 1-keV ion-irradiated sapphire crystals as potential VUV to NIR window materials of fusion reactors Open

Keisuke Iwano, Kohei Yamanoi, Y. Iwasa, Kazuyuki Mori, Yuki Minami , et al. · 2016

We investigate the optical transmittances of ion-irradiated sapphire crystals as potential vacuum ultraviolet (VUV) to near-infrared (NIR) window materials of fusion reactors. Under potential conditions in fusion reactors, sapphire crystal…

A pathway to laser fusion energy in Japan Open

H. Azechi · 2016

High-density compression of DT to one thousand times its liquid density is the critical path of inertial fusion and was demonstrated in Japan and US in late 1980's. The Osaka group has achieved high-density compression that meets one of th…

Electron transport estimated from electron spectra using electron spectrometer in LFEX laser target experiments Open

T. Ozaki, M. Hata, Kazuki Matsuo, Sadaoki Kojima, Yasunobu Arikawa , et al. · 2016

Hot electrons which are generated from targets irradiated by a high-intense laser are measured by two electron spectrometers (ESMs). However, total electron energy observed by the ESM is only less than 1%. Hot electrons are confined by sel…

The status of Fast Ignition Realization Experiment (FIREX) and prospects for inertial fusion energy Open

H. Azechi · 2016

Here we report recent progress for the fast ignition inertial confinement fusion demonstration. The fraction of low energy (< 1 MeV) component of the relativistic electron beam (REB), which efficiently heats the fuel core, increases by a f…

Direct heating of compressed core by ultra-intense laser Open

Atsushi Sunahara, T. Johzaki, H. Sakagami, Hideo Nagatomo, K. Mima , et al. · 2016

We propose a new scheme for heating an imploded core in the fast-ignition scheme. In this method, a heating laser irradiates an imploded core plasma directly. The accelerated fast-ions as well as fast-electrons heat the core. Two-dimension…

Energy distribution of fast electrons accelerated by high intensity laser pulse depending on laser pulse duration Open

Sadaoki Kojima, Yasunobu Arikawa, A. Morace, M. Hata, Hideo Nagatomo , et al. · 2016

The dependence of high-energy electron generation on the pulse duration of a high intensity LFEX laser was experimentally investigated. The LFEX laser (λ = 1.054 and intensity = 2.5 – 3 x 1018 W/cm2) pulses were focused on a 1 mm3 gold cub…

Mechanical design of experimental apparatus for FIREX cryo-target cooling Open

A. Iwamoto, T. Norimatsu, M. Nakai, H. Sakagami, Shinsuke Fujioka , et al. · 2016

Mechanical design of an experimental apparatus for FIREX cryo-target cooling is described. Gaseous helium (GHe) sealing system at a cryogenic environment is an important issue for laser fusion experiments. The dedicated loading system was …

Direct heating of imploded plasma in the fast ignition Open

Atsushi Sunahara, T. Johzaki, Hideo Nagatomo, K. Mima, Hiroyuki Shiraga , et al. · 2016

We propose the direct heating of an imploded plasma core by ultra-intense lasers in inertial confinement fusion, to increase the heating coupling efficiency. In this scheme, both fast-electrons and fast-ions heat the plasma core. Experimen…

Cool-down performance of the new apparatus for fuel layering demonstrations of FIREX targets Open

A. Iwamoto, T. Norimatsu, M. Nakai, H. Sakagami, H. Shiraga , et al. · 2016

FIREX targets have been developed under two layering strategies: foam shell and cone guide laser heating methods. Basic studies have been conducted by the collaboration research between ILE and NIFS. Then the next stage requires the charac…

Progress Towards a Laser Produced Relativistic Electron-Positron Pair Plasma Open

Hui Chen, J. Bonlie, R. Cauble, Frederico Fiúza, W. H. Goldstein , et al. · 2016

Here, a set of experiments has been performed exploring unique characteristics of pair jets and plasmas at several energetic short-pulse laser facilities including Titan at Livermore and OMEGA EP in Rochester, as well as the Osaka LFEX and…

Beyond Extreme Ultra Violet (BEUV) Radiation from Spherically symmetrical High-Z plasmas Open

Kensuke Yoshida, Shinsuke Fujioka, Takeshi Higashiguchi, Teruyuki Ugomori, Nozomi Tanaka , et al. · 2016

Photo-lithography is a key technology for volume manufacture of high performance and compact semiconductor devices. Smaller and more complex structures can be fabricated by using shorter wavelength light in the photolithography. One of the…

The diagnostics of the energy coupling efficiency in the Fast Ignition integrated experiment Open

Yasunobu Arikawa, Shinsuke Fujioka, A. Morace, Zhe Zhang, Takahiro Nagai , et al. · 2016

The energy coupling efficiency (CE) in Fast Ignition (FI) laser fusion was studied at GEKKO XII and LFEx laser facility by using newly developed targets and plasma diagnostic instruments. The gated-liquid scintillator neutron detectors had…

Hot electron spectra on advanced targets in FIREX Open

T. Ozaki, Atsushi Sunahara, H. Shiraga, Yasunobu Arikawa, Shinsuke Fujioka , et al. · 2016

The traditional fast ignition scheme is that a compressed core created by an imploding laser is auxiliary heated and ignited by the hot electrons (produced by a short pulse laser guided through the cone and guided under-dense plasma). Howe…

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