A5078152665- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Laser Material Processing Techniques
- Nuclear Physics and Applications
- Magnetic confinement fusion research
- Laser Design and Applications
- Ion-surface interactions and analysis
- Distributed and Parallel Computing Systems
- Atomic and Molecular Physics
- Energetic Materials and Combustion
- Parallel Computing and Optimization Techniques
- Ocular and Laser Science Research
- Plasma Diagnostics and Applications
- Combustion and Detonation Processes
- Fusion materials and technologies
- Particle accelerators and beam dynamics
- Electromagnetic Launch and Propulsion Technology
- Advanced Data Storage Technologies
- Nuclear Materials and Properties
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Mass Spectrometry Techniques and Applications
- Pulsed Power Technology Applications
National Institute for Fusion Science
2015-2024
National Institutes of Natural Sciences
2008-2021
Nagoya University of Foreign Studies
2021
Kyoto University Institute for Chemical Research
2020
Osaka Sangyo University
2020
Osaka University
1996-2020
Kyoto University
2020
Institute for Laser Technology
2016
Tokyo Institute of Technology
2016
Life Science Institute
2016
The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of pre-compressed plasma core with high-intensity short-pulse an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF sparks. This avoids quench caused hot spark mixing surrounding cold fuel, which crucial problem currently pursued scheme. High-intensity lasers efficiently produce...
Abstract Using one of the world most powerful laser facility, we demonstrate for first time that high-contrast multi-picosecond pulses are advantageous proton acceleration. By extending pulse duration from 1.5 to 6 ps with fixed intensity 10 18 W cm −2 , maximum energy is improved more than twice (from 13 33 MeV). At same time, laser-energy conversion efficiency into MeV protons enhanced an order magnitude, achieving 5% above duration. The energies observed discussed using a plasma expansion...
It is widely believed that depletion force causes formation of colloidal crystal or flocculation in the stable suspension mixed with nonadsorbing polymers. This works between a particle and plane, which can be regarded as sphere infinite radius. We report novel technique enables us to measure working glass surface using laser radiation pressure. found observed almost coincides predicted one.
A petawatt laser for fast ignition experiments (LFEX) system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 beams, has been constructed beside the GEKKO-XII facility demonstrating efficient heating dense plasma up to temperature under auspices Fast Ignition Realization EXperiment (FIREX) project [H. Azechi Nucl. Fusion 49, 104024 (2009)]. In FIREX experiment, cone attached spherical target containing fuel...
In an inhomogeneous plasma, low-frequency solitary waves, generated by superintense laser pulses, are accelerated towards the plasma-vacuum interface where they radiate their energy in form of electromagnetic bursts. The transverse inhomogeneity plasma inside self-focusing radiation channel leads to guiding waves. These waves excite a two-ribbon magnetic field structure wake. phenomena have been studied with two-dimensional particle-in-cell simulations and expected be observed present-day...
Electron energy characteristics generated by the irradiation of ultraintense laser pulses onto solid targets are controlled using cone targets. Two parameters characterizing laser-cone interaction introduced, which angle and ratio spot size to tip size. By changing these parameters, absorption rate, irradiance at tip, electron acceleration side wall controlled. The optimum for fast ignition 30° with double-cone geometry, a comparable core size, pulse about four times Cone have possibility...
Based on the successful result of fast heating a shell target with cone for beam injection at Osaka University in 2002 using PW laser (Kodama et al Nature 418 933), FIREX-1 project was started 2004. Its goal is to demonstrate fuel up 5 keV an upgraded beam. For this purpose, LFEX laser, which can deliver energy to10 kJ 0.5–20 ps pulse its full spec, has been constructed addition Gekko-XII system Institute Laser Engineering, University. It activated and became operational since 2009....
For enhancing the core heating efficiency in electron-driven fast ignition, we proposed electron beam guiding using externally applied longitudinal magnetic fields. Based on PIC simulations for FIREX-class experiments, demonstrated sufficient performance collisional dense plasma by kT-class external fields case with moderate mirror ratio (~<10 ). Boring of field was found through formation pipe structure due to resistive effects, which indicates a possibility high higher laser intensity...
Laser pulse contrast exceeding 1011 was demonstrated on a kilojoule-class petawatt laser for fast ignition experiments (LFEX) system [J. Phys. IV France133, 81 (2006)10.1051/jp4:2006133016] by implementing 2 in. plasma mirror. beams of up to 1.2 kJ striking the mirror with duration 1.5 ps were reflected and focused onto target without significant distortions in focal spot. Transmitted light from reveals that it has high reflectivity before main peak. The estimated at 1 ns No preformed...
Fast isochoric laser heating is a scheme to heat matter with relativistic intensity ($>{10}^{18}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) pulse for producing an ultrahigh-energy-density (UHED) state. We have demonstrated efficient fast of compressed dense plasma core multipicosecond kilojoule-class petawatt and assistance externally applied kilotesla magnetic fields guiding electrons the plasma. A UHED state 2.2 PPa achieved experimentally 4.6 kJ total energy that one order magnitude...
A fully three-dimensional Rayleigh-Taylor instability of the pusher-fuel contact surface in a spherically stagnating system is investigated with use new fluid code impact - 3d. Linear growth rates simulations agree quite well analytical values which include spherical-geometry effects. Saturation amplitudes exponential and free-fall speed following saturation are found to be, respectively, larger faster than those 2D simulations. Nonlinear bubble-spike structures also studied detail.
In the fast ignition (FI) scheme, at first, high-density fuel core plasma is assembled by implosion laser, and then heated petawatt laser to achieve a fusion burning condition. The formation of one key issues for FI. A typical target FI shell fitted with reentrant gold cone make pass heating laser. ablated interferes dynamics, which quite different from that conventional central-hot-spot approach. Therefore, dynamics nonspherical must be controlled assemble high density areal density....
Since the approval of first phase Fast-Ignition Realization Experiment (FIREX-I), we have devoted our efforts to designing advanced targets and constructing a petawatt laser, which will be most energetic laser in world. Scientific technological improvements are required efficiently heat core plasma. There two methods that can used enhance coupling efficiency heating thermal energy compressed plasma: adding low- Z foam layer inner surface cone employing double cone. The implosion performance...
The effect of pre-plasma on core heating in cone-guiding fast ignition is evaluated by two-dimensional particle-in-cell (PIC) and Fokker–Planck (FP) simulations. If the long-scale exists cone, generated electron energy becomes too high for effective heating. As a result, coupling from laser to η L→core reduced 80% compared with case without pre-plasma. Even pre-plasma, obtained simulation smaller than that required 5 keV FIREX-I. In order enhance , we propose new target design ‘extended...
A series of experiments were carried out to evaluate the energy-coupling efficiency from heating laser a fuel core in fast-ignition scheme laser-driven inertial confinement fusion. Although is determined by wide variety complex physics, intense plasma interactions properties high-energy density plasmas and transport relativistic electron beams (REB), here we simplify physics breaking down into three measurable parameters: (i) energy conversion ratio REB, (ii) probability collision between...
One of the most advanced fast ignition programmes is realization experiment (FIREX). The goal its first phase to demonstrate temperature 5 keV, followed by second ignition-and-burn. series FIREX-I, from late 2010 early 2011, has demonstrated a high (>10%) coupling efficiency laser thermal energy compressed core, suggesting that can be achieved at below 10 kJ. Further improvement expected introducing laser-driven magnetic fields.
Abstract The dependence of the mean kinetic energy laser-accelerated relativistic electrons (REs) on laser intensity, so-called ponderomotive scaling, explains well experimental results to date; however, this scaling is no longer applicable multi-picosecond (multi-ps) experiments. Here, production REs was experimentally investigated via multi-ps laser–plasma-interaction (LPI). lower slope temperature shows little pulse duration and close value, while higher appears be affected by duration....
We succeeded in getting 14.9 TFLOPS performance when running a plasma simulation code IMPACT-3D parallelized with High Performance Fortran on 512 nodes of the Earth Simulator. The theoretical peak is 32 TFLOPS, which means 45% was obtained HPF. an implosion analysis using TVD scheme, performs three-dimensional compressible and inviscid Eulerian fluid computation explicit 5-point stencil scheme for spatial differentiation fractional time step integration. mesh size 2048x2048x4096, third...
Abstract In fast ignition research, the clarification of core heating mechanism is one most critical issues. To understand and identify crucial physics in heating, we developed integrated interconnecting code FI 3 carried out simulations for experiments with cone-guided targets. It was found that scale length pre-plasma at inner-surface cone density gap contact surface between tip imploded plasma strongly affect efficiency heating. case laser intensity 10 20 W/cm 2 duration 1 ps, 1.5 µm...
When ultraintense laser pulses irradiate solid targets with a large incident angle, quasistatic magnetic and electric fields are induced, which confine electrons along the target surface in an electrostatic vector potential well. In this case, resonantly accelerated by field inside By acceleration process, high energy effectively generated whose temperature well exceeds ponderomotive energy. The optimum conditions for realizing its scalings given. Capillary type shown to have advantage...
To enhance the core heating efficiency in fast ignition laser fusion, concept of relativistic electron beam guiding by external magnetic fields was evaluated integrated simulations for FIREX class targets. For cone-attached shell target case, performance is deteriorated applying since considerably deformed and most electrons are reflected due to mirror formed through implosion. On other hand, case solid ball target, implosion more stable under kilo-tesla-class field. In addition, feasible...
On the basis of one-dimensional coupled PIC and Fokker–Planck simulations, core heating properties different cone materials for sub-ignition class experiments cone-guiding fast ignition have been studied. When Au is used as a material tip, atoms ionize to high charge state during interaction with pulse in few hundreds femtoseconds. Because extreme photon pressure, starts interact directly solid-density tip after density slope steepened. In addition, electrons return current are strongly...
The compression of an external magnetic field by a laser-driven implosion is studied using the two-dimensional resistive magneto-radiation hydrodynamic simulation code for electron-beam guiding in fast ignition. results show that it possible to compress 1 kT (107 G); however, strong affects dynamics because suppression electron heat flux crosses lines. This result suggests care must be taken design target and initial conditions ignition with not only control hot transport but also form...