[en] The stable water isotopes (SWIs) (δ18O and δD) are used as an indicator of the intensity of the atmospheric hydrological cycle due to their large variability in time and space. Although data about vapor isotope ratio with high frequency and high resolution are now available by satellite observations and spectroscopic analyses, there is some room for discussion on the variability of isotope ratios in vapor and precipitation related to cloud microphysical processes. Here, we incorporated SWI tracer into the latest version of a global cloud system resolving model (the Nonhydrostatic Icosahedral Atmospheric Model (NICAM)), iso-NICAM, and investigated the contribution of cloud microphysical processes to the variability of isotope ratios in precipitation and vapor. One of the merits used NICAM is that its physical process can cover from low spatial resolution to high spatial resolution. We conducted two mode simulations (GCM and CRM). The GCM mode simulation is based on the Arakawa-Schubert scheme as convective parameterization and a large-scale condensation scheme as the cloud physical process. In contrast, the CRM mode simulation is based on the a single-moment bulk cloud microphysics scheme with 6 water categories as cloud microphysical scheme, convective parameterization scheme was not used. These simulations are set to about 223 km of horizontal mesh resolution and 78 vertical layers. We conducted an AMIP-type climate experiment for one year from 1979. The simulated precipitation δ18O showed the latitude effect pattern (high δ18O in low latitude region, low δ18O in high latitude region), but those values in the CRM mode was slightly lower than that in the GCM mode . The simulated precipitation δ18O in the CRM mode was lower in high altitude or inland regions compared with those in the GCM mode . Besides, the precipitation d-excess in the CRM mode shows large spatial variability compared with the GCM mode. Although the low spatial resolution was set in this study, these simulations indicated cloud microphysical processes are important for understanding the variability of isotope physics. We will conduct these simulations with finer spatial resolution and a more extended simulation period.

[en] The analytical formulation on the elasto-visco-plastic problems of general, moderately thick shells of revolution subjected to axisymmetrical load is developed by extension of the Reissner theory in elastic shells where a consideration on the effect of shear deformations is given. The authors employ as constitutive relation of the shell materials Perzyna's equation where in the plastic range the viscosity of the material is considered. The criterion for yielding used in this analysis is the von Mises yield theory. The basic differential equations derived for elasto-visco-plastic problems are numerically solved by a finite difference method, and the solutions are obtained by integration of the incremental values. As a numerical example, the elasto/visco-plastic deformation of pressure vessels is analyzed, and the results are compared with those from the classical theory which neglects the effect of shear deformations. (orig.)

[en] Laser-plasma interaction generates a high energy electron beam. The laser contrast ratio is one of the important parameters for laser acceleration due to pre-plasma effects. For the high laser contrast ratio, a 140 MeV monoenergetic electron beam with a charge of 100 pC is obtained. For the low laser contrast ratio; a low quality electron beam or no electron beam are generated, because the pre-pulse blowout plasma electrons and put into disorder the plasma before the main pulse interacting the plasma. The laser contrast ratio should be high in order to generate a high quality electron beam with a high charge.

[en] Towards our final goal, such as to establish the laser-driven proton accelerator for the medical application, one of the most important things to establish is to develop the proton transport system. In this continuous work, we demonstrate the focusing system of the laser-driven proton beam with permanent magnet qadrupoles (PMQs), with which a 2.4 MeV laser-driven proton beam, having a divergence angle of ∼10 degrees at birth, is focused to a spot whose size is 3x8mm² at 640mm downstream from the target.

[en] We have performed simultaneous proton and X-ray imaging with an ultra-short and high-intensity Ti: Sap laser system. More than 10¹⁰ protons, whose maximum energy reaches 2.5 MeV, were delivered within a ∼ps bunch. At the same time, keV X-ray is generated at almost the same place where protons are emitted. We have performed the simultaneous imaging of the copper mesh by using proton and x-ray beams, in practical use of the characteristics of the laser produced plasma that it can provide those beams simultaneously without any serious problems on synchronization

[en] A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse. The wakefield is generated by a laser pulse; the second laser pulse collides with the first pulse at 180 deg. and at 135 deg. realizing optical injection of an electron bunch. The electron bunch has high stability and high reproducibility compared with single pulse electron generation. In the case of 180 deg. collision, special measures have been taken to prevent damage. In the case of 135 deg. collision, since the second pulse is countercrossing, it cannot damage the laser system.

[en] We demonstrate laser-ion acceleration from a near-critical density plasma, using amplified spontaneous emission (ASE) to convert a solid foil target into a lower-density target. In order to investigate the target density dependence of the laser-ion acceleration, two cases were investigated for which the ASE intensity differed by three orders of magnitude. In the low contrast case the beam centre for higher energy protons is shifted closer to the laser-propagation direction of 45 degrees, while the centre of lower-energy beam remains near the target normal direction. We show that a near-critical density plasma can be used to control proton beam direction based on its energy. (authors)

[en] High-power laser contrast is challenging to measure, especially in the real target irradiation conditions. We present a convenient and relatively simple contrast diagnostic technique based on the measurement of target specular reflectivity at full laser power. The reflectivity remains high even at intensities above 10¹⁹ W/cm² in the case of a high-contrast prepulse-free laser. On the contrary, the specular reflectivity drops in the case of lower contrast, due to the beam break-up and increased absorption caused by the preformed plasma. The technique was demonstrated using three different laser systems with several contrast conditions: Astra (CLF, RAL), TiS laser at APRI, GIST, and J-KAREN (APRC, JAEA).

[en] As a benchmark experiment to realize a novel and compact laser driven proton accelerator whose significant features are high number density in a short pulse width (∼ns), 2.4 MeV laser driven proton beam is stably focused at 1 Hz repetition rate by using a pair of permanent quadrupole magnets (PMQs) with large apertures whose diameters and field strengths are 3.5 cm and 55 T/m for the first and 2.3 cm and 60 T/m for the second magnets, respectively. The proton beam has been focused to a focal spot of 3x8 mm² in horizontal and vertical direction (full width at half maximum) at 650∼mm from the source, which is well reproduced by the simulation. The further optimization of the focusing system will sure to pave a way to the novel proton accelerator with which we can investigate the physics appeared in the short time scale as well as that in a high energy density matter, oncology, astrophysics, and so on.

[en] A pair of conventional permanent magnet quadrupoles is used to focus a 2.4 MeV laser-driven proton beam at a 1 Hz repetition rate. The magnetic field strengths are 55 and 60 T/m for the first and second quadrupoles, respectively. The proton beam is focused to a spot with a size of less than ∼3x8 mm² at a distance of 650 mm from the source. This result is in good agreement with the Monte Carlo particle trajectory simulation