Supershort avalanche electron beam (SAEB) plays an important role in nanosecond-pulse discharges. this paper aims at reviewing experiments results on characteritics of SAEB and its spectra in different gases in nanosecond-pulse discharges. All the joint experiments were carried in the Institute of High Current Electronics of the Russian Academy of Sciences and the Institute of Electrical Engineering of the Chinese Academy of Sciences. In these experiments, the generation of a SAEB in SF6 in an inhomogeneous electric field was studied on three generators with pulse rise times of 0.3, 0.5 and ~2 ns. Firstly, the comparison of SAEB parameters in SF6 with those obtained in other gases (air, nitrogen, argon, and krypton) is introduced. Secondly, the SAEB spectra in SF6 and air at pressures of 10 kPa (75 torr), and 0.1 MPa (750 torr) are reviewed and discussed. Finally, 1.5-D theoretical simulation of the supershort pulse of the fast electron beam in a coaxial diode filled with SF6 at atmospheric pressure is described. the simulation was carried out in the framework of hybrid model for discharge and runaway electron kinetics. the above research progress can provide better understanding of the investigation into the mechanism of nanosecond-pulse discharges.

Recent advances in experimental techniques and data processing allow in situ determination of mineral crystal structure and chemistry up to Mbar pressures in a laser-heated diamond anvil cell (DAC), providing the fundamental information of the mineralogical constitution of our Earth's interior. this work highlights several recent breakthroughs in the field of high-pressure mineral crystallography, including the stability of bridgmanite, the single-crystal structure studies of post-perovskite and H-phase as well as the identification of hydrous minerals and iron oxides in the deep lower mantle. the future development of high-pressure crystallography is also discussed.

Dynamics and spectral transmission of Al plasma produced by extreme ultraviolet (EUV) irradiation of 0.75-mm thick Al foil is investigated. the EUV radiation with the peak power density in the range of 0.19-0.54 TW/cm² is provided by Z-pinch formed by W multiwire array implosion in the Angara-5-1 facility. Geometry of the experiment ensures that there are no plasma fluxes from the pinch toward the Al foil and plasma. the same EUV source is used as a back illuminator for obtaining the absorption spectrum of Al plasma in the wavelength range of 5-24 nm. It comprises absorption lines of ions Al⁴⁺, Al⁵⁺, Al⁶⁺, Al⁷⁺. Analysis of relative intensities of the lines shows that those ions are formed in dense Al plasma with a temperature of ~20 eV. Dynamics of Al plasma has been investigated with transverse laser probing. We have also performed radiation-gas-dynamics simulations of plasma dynamics affected by external radiation, which includes self-consistent radiation transport in a plasma shell. the simulations show good agreement with an experimental absorption spectrum and with experimental data concerning plasma dynamics, as well as with the analysis of line absorption spectrum. this confirms the correctness of the physical model underlying these simulations.

In order to measure the shock initiation behavior of JOB-9003 explosives, Al-based embedded multiple electromagnetic particle velocity gauge technique has been developed. In addition, a gauge element called the shock tracker has been used to monitor the progress of the shock front as a function of time, thus providing a positionetime trajectory of the wave front as it moves through the explosive sample. the data is used to determine the position and time for shock to detonation transition. All the experimental results show that the rising-up time of Al-based electromagnetic particle velocity gauge is very short (<20 ns); the reaction-build-up velocity pro.les and the positionetime for shock to detonation transition of HMX-based plastic bonded explosive (PBX) JOB-9003 with 1-8 mm depth from the origin of the impact plane under different initiation pressures were obtained with high accuracy.

An overview of diagnostic tools e test limiters and collector probes e used over the years for material migration studies in the TEXTOR tokamak is presented. Probe transfer systems are shown and their technical capabilities are described. this is accompanied by a brief presentation of selected results and conclusions from the research on material erosion e deposition processes including tests of candidate materials (e.g. W, Mo, carbon-based composites) for plasma-facing components in controlled fusion devices. the use of tracer techniques and methods for analysis of materials retrieved from the tokamak are summarized. the impact of research on the reactor wall technology is addressed.