Ultrafast optical probing is a widely used method of underdense plasma diagnostic. In relativistic plasma, the motion blur limits spatial resolution in the direction of motion. For many high-power lasers the initial pulse duration of 30–50 fs results in a 10–15 μm motion blur, which can be reduced by probe pulse post-compression. Here we used the compression after compressor approach [Phys.-Usp. 62, 1096 (2019); JINST 17 P07035 (2022)], where spectral broadening is performed in thin optical plates and is followed by reflections from negative-dispersion mirrors. Our initially low-intensity probe beam was down-collimated for a more efficient spectral broadening and higher probe-to-self-emission intensity ratio. The setup is compact, fits in a vacuum chamber and can be implemented within a short experimental time slot. We proved that the compressed pulse retained the high quality necessary for plasma probing.

To classify the clinical characteristics of ocular toxocariasis in Japan, the prevalence of antibodies to Toxocara antigens was examined in patients with uveitis of unknown aetiology. From 1982 to 1993, serum specimens of 383 cases and intraocular fluid samples of 22 cases were serologically screened for Toxocara infection with five immunodiagnostic tests. Fifty-five sera and 11 intravitreous fluid samples were estimated to have significantly high antibody levels against larval excretory–secretory (ES) antigens of T. canis. Eight cases were positive in both serum and vitreous fluid, and three were positive only in the vitreous fluid. Among the 58 antibody positive samples, 20 cases were omitted due to a lack of detailed description of ocular findings. The remaining 38 cases are described in this study. Of these 38 cases, 34 (89%) were older than 20 years of age. Ocular lesions were located in the posterior fundus in 11 cases, in the peripheral fundus in 18 cases, and in both areas in seven cases. Of the eight cases in which papillary oedema or redness was observed, chorioretinal lesions were also present in seven of them. Tractional retinal detachment was present in five cases. These observations suggest that ocular toxocariasis in Japan has a different clinical profile compared with those in the other countries, and indicate a need for revised classification of ocular toxocariasis.

Tight focusing with very small f-numbers is necessary to achieve the highest at-focus irradiances. However, tight focusing imposes strong demands on precise target positioning in-focus to achieve the highest on-target irradiance. We describe several near-infrared, visible, ultraviolet and soft and hard X-ray diagnostics employed in a ∼1022 W/cm2 laser–plasma experiment. We used nearly 10 J total energy femtosecond laser pulses focused into an approximately 1.3-μm focal spot on 5–20 μm thick stainless-steel targets. We discuss the applicability of these diagnostics to determine the best in-focus target position with approximately 5 μm accuracy (i.e., around half of the short Rayleigh length) and show that several diagnostics (in particular, 3$\omega$ reflection and on-axis hard X-rays) can ensure this accuracy. We demonstrated target positioning within several micrometers from the focus, ensuring over 80% of the ideal peak laser intensity on-target. Our approach is relatively fast (it requires 10–20 laser shots) and does not rely on the coincidence of low-power and high-power focal planes.

Solid solutions of fluoromicas WMg2Li(Si4−x GexO10)F2 (W = K, Na, Li. 0 ≦ x ≦ 4), which were closely related to taeniolite, were synthesized and the effect of the isomorphic substitution Ge for Si and also the interlayer cations Li, Na and K respectively upon hydration and dehydration were studied by X-ray diffraction, infrared and thermal analysis. The Na- and Li-series exhibit swelling with water, whereas the K-series does not. The increase of tetrahedral germanium substitution reduces hydration and also lowers the dehydration temperature of hydrates in both the Na- and Li-series. The reasons for such tendencies are discussed. Repulsion between interlayer cations and tetrahedral cations seems to play the dominant role. K in opposition to the smaller interlayer cations Li and Na respectively fits in the interlayer sites of the mica structure and lowers repulsion. By increasing the substitution Ge for Si interionic distances become greater and repulsion also decreases.

The interaction of femtosecond ultra-intense laser pulses with clusters increases absorption of the incident laser light compared with the interaction with solid targets and leads to enhanced generation of different quantum beams with unique parameters. Future investigations of such interaction urgently need detailed modeling and optimization of cluster parameters, for instance, in order to obtain the clusters with desired size, or some specific spatial configuration of the target etc. A numerical model of gas-cluster targets production by the nozzle flows of gases and binary mixtures is presented. Some previous results of the model utilization are summarized, and some new results are given. Techniques of experimental verification of the numerical results are discussed.

In this paper, a study on a fusion reactor core is presented in heavy-ion inertial fusion (HIF), including the heavy-ion beam (HIB) transport in a fusion reactor, an HIB interaction with a background gas, the reactor cavity gas dynamics, the reactor gas backflow to the beam lines, and an HIB fusion reactor design. The HIB has remarkable preferable features to release the fusion energy in inertial fusion: in particle accelerators HIBs are generated with a high driver efficiency of about 30–40%, and the HIB ions deposit their energy inside of materials. Therefore, a requirement for the fusion target energy gain is relatively low, that would be ~50 to operate an HIF fusion reactor with a standard energy output of 1 GW of electricity. In a fusion reactor, the HIB charge neutralization is needed for a ballistic HIB transport. Multiple mechanical shutters would be installed at each HIB port at the reactor wall to stop the blast waves and the chamber gas backflow, so that the accelerator final elements would be protected from the reactor gas contaminant. The essential fusion reactor components are discussed in this paper.

It is now firmly established that a small anisotropy of the galactic cosmic rays exists, observable from Earth as a variation of intensity in sidereal time. The problem now is to determine more clearly the characteristics of the anisotropy and, in particular, its detailed spatial structure and how it depends upon the energy and composition of the cosmic rays. This is a very difficult task and, in the final analysis, may not be fully achievable from Earth-based observations. The purpose of the present paper is to describe briefly an installation now operating in Tasmania to provide further information on the spatial structure of the anisotropy.

This paper summarises Ginga X-ray observations of SN 1987 A.

As a method to evaluate high-temperature equation of state (EOS) data of fissile materials precisely and safely, we numerically examined an experimental setup based on a sub-range fissile target and a high-intensity short-pulsed heavy-ion beam. As an example, we calculated one-dimensional hydrodynamic motion of a uranium target with ρ = 0.03ρsolid (ρsolid ≡ solid density = 19.05 g/cm3) induced by a pulsed 23Na+ beam with a duration of 2 ns and a peak power of 5 GW/mm2. The projectile stopping power was calculated using a density- and temperature-dependent dielectric response function. To heat the target uniformly, we optimized the experimental condition so that the energy deposition could occur almost at the top of the Bragg peak. The energy deposition inhomogeneity could be reduced to ±5% by adjusting the incident energy and the target thickness to be 2.02 MeV/u and 180 μm, respectively. The target could be heated homogeneously up to kT =7 eV well before the arrival of the rarefaction waves at the center of the target. In principle, the EOS data can be evaluated by iteratively adjusting the data embedded in the hydro code until the measured hydrodynamic motion is reproduced by the calculation. This method is consistent with the conditions of nuclear nonproliferation, because a very small amount of fissile material is enough to perform the experiment, and no shock compression occurs in the target.

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

A discharge-emission spectrometer and a cavity ringdown spectrometer have been developed to aid in the solution to the diffuse interstellar band (DIB) problem. A hollow cathode was used to generate molecular ions in a discharge because it has been suggested that molecular ions are probable DIB candidates. The discharge was produced by a pulsed voltage of 1300–1500 V. A wide wavelength range of optical emission from the discharge was examined by a HORIBA Jobin Yvon iHR320 monochromator. The dispersed discharge emission was detected by a photomultiplier and was recorded via a lock-in amplifier. The 2B3u–X2B2g electronic transition of the butatriene cation H2CCCCH2+ was observed in the discharge emission of 2-butyne H3CCCCH3. The frequency of the electronic transition was measured to be 20381 cm−1, and a comparison study was made with known DIB spectra.

The resolution of the discharge-emission spectrometer is insufficient to make precise comparisons between laboratory frequencies and astronomically observed DIB spectra. We therefore developed the cavity ringdown spectrometer using the same hollow cathode. The high sensitivity of this spectrometer was confirmed by the observation of the forbidden band of O2.