A fully automated Langmuir probe system capable of operating simultaneously with beam extraction has been developed and commissioned for the negative hydrogen ion source testbeds at IPP Garching. It ...allows the measurement of temporal and spatial distributions of the plasma parameters within a single plasma pulse ( < 5 s). This system can operate even in the presence of multi-harmonic RF interference due to a novel transformer-based RF compensation system. Analysis methods of the probe data are described in the paper along with a discussion of errors. Measurements of the plasma parameters for RF powers (30-80 kW) and source pressures (0.3-0.8 Pa) both in plasma generation region and near the plasma grid have been carried out. The plasma generation region has both a high density ( > 1018 m-3) and hot (Te > 10 eV) plasma with bi-Maxwellian electron energy distribution at low pressures. The plasma found near the plasma grid is very different being of low density ( < =1017 m-3) and very cold (Te < 2 eV). This plasma is also strongly influenced by the presence of caesium, the potential of the plasma grid, and if an ion beam is extracted from the source. Caesium strongly reduces the plasma potential of the source and enhances the negative ion density near the plasma grid. Extracting an ion beam is observed to reduce the electron density and increase the potential near the plasma grid. Applying a potential greater than the plasma potential to the plasma grid is found to significantly decrease the electron density near the plasma grid.
Measurements of the brightness temperature and compressibility of a dense silicon plasma formed by powerful shock waves (SWs) passing through a single‐crystal sample have been carried out. Plane SWs ...were created using an explosive technique: the traditional plane acceleration of a steel driver plate made it possible to obtain pressures in silicon up to 133 GPa, and the use of “Mach” cumulative generators realized the pressures up to 510 GPa. The shock Hugoniot of silicon was determined by the impedance matching with α‐quartz as the reference. The intensity of emitted thermal radiation was measured in the infrared range λ ∼ 1.5 μm, where silicon is optically transparent, and in the visible range of the spectrum. A significant (up to five times) understatement of the measured values of the brightness temperature in comparison with the values calculated by the equation of state was found. Taking into account the reflective properties of the SW in silicon does not lead to an agreement with the experiment. The estimates of relaxation processes behind the shock front suggest the presence of a zone of the establishment of ionization equilibrium with a width of ∼10 μm.
The
goal
of the study – development of specific methodical reasoned proposals on improvement of the mechanism for ensuring sustainable development of the national banking system and its security ...against external challenges and threats to cyberspace. The
scientific novelty
consists in a comprehensive analysis of the processes of ensuring the cyber stability of the Russian banking system in the context of escalation of external challenges and threats to the digital economy. The authors used the following methods: general scientific (observation, comparison, measurement, analysis and synthesis, logical reasoning method), specific scientific (static analysis, peer review, graphical method). In the article conducted a critical review of domestic and foreign scientific literature and practical recommendations to ensure the protection of the banking institution from cyber threats in the digital economy; presented a comparative analysis of the organization of the cybersecurity system in the Russian and foreign banking systems; done multidimensional statistical analysis of cyber threats for Russian banks; substantiated recommendations and proposals on organizational, economic and legal improvement of the system of protection of Russian banks from internal and external cyber threats. As a
result
, it is shown that the main problem points (zones) of the banking system, creating the prerequisites for the occurrence of cyber-risks are: 1) there is no exchange of information on cyber-attacks and their mechanisms; 2) banks interact inefficiently with the state regulator of Internet – Roskomnadzor; 3) low level of competence of bank employees who are responsible for cybersecurity; 4) limited budget of small and medium-sized banks that wouldn’t allow them to care independent cyber-protection units; 5) growing popularity of new fintech services and new fintech companies. The author draws a
conclusion
that the following measures are necessary for organizational, economic and legal improvement of the system of protection of Russian banks from internal and external cyber threats: the processes of development of banking ecosystems should be intensified; a federal interbank register of cyber fraudsters must be created; a single banking «polygon» for testing cyber threats needs to be developed.
The size, form and distribution function of catalyst particles define the quality of synthesized arrays of carbon nanotubes. In this work, we study the kinetics of catalyst particle formation from ...the thin nickel film (9 nm) deposited on the silicon substrate (SiO2/Si) with a buffer layer of niobium nitride at the temperature of 880 °C. In the experiment, we have obtained the time dependences of the average radius, average height and concentration of nickel particles. The experimental data are satisfactorily described by simulations based on the wetting transition theory. Comparison of the simulation results and experimental data allows us to estimate the effective interaction potential between the nickel film and buffer layer of niobium nitride. Besides, we have estimated the viscosity of the nickel confirming an undercooled liquid state of the nanosized nickel film at the temperature of 880 °C.
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Integrated field-emission devices and integrated circuits (ICs) based on them are a promising direction in microelectronics, which is associated with the use of low-voltage and stable field ...emitters based on nanomaterials, such as carbon nanotubes (CNTs). The planar design of the field-emission device makes it possible to form CNTs at the end of a thin catalyst film 1–50 nm thick. The paper presents the results of the implementation of an integrated technology for manufacturing planar field-emission diodes with a CNT cathode formed at the end of a thin conducting film. The CNTs are grown by chemical-vapor deposition. A thin film of initially amorphous Co–Nb–N–(O) alloy is used as the growth catalyst. A feature of the technology is the crystallization of Co–Nb–N–(O) alloy during heating in the process of chemical-vapor deposition. As a result, Co nanoparticles are formed on the alloy surface, which catalyze the growth of CNTs. It is shown that this specific feature makes it possible to form CNTs locally, only in open areas of the Co–Nb–N–(O) alloy, for example, at the ends of a thin film. The choice of the Co–Nb–N–(O) alloy is substantiated. The stages of formation of planar field-emission diodes on a silicon substrate are described using standard manufacturing processes. The results of measuring the
I
–
V
characteristics of devices are presented. It is shown that the type of
I
–
V
characteristics is determined by the field emission characteristic of CNTs. The developed technological method for the local synthesis of CNTs at the ends of topologically formed regions of a thin Co–Nb–N–(O) alloy film can be incorporated into an integrated technology for the formation of planar field-emission devices.
The shock compressibility of single-crystal silicon is experimentally studied in the pressure range of 280 to 510 GPa. Shock waves are created using Mach’s explosive cumulative generators. The ...parameters of shock waves are determined by the impedance matching method, and single-crystal quartz is used as a ref-erence substance. The results agree well with the
ab initio
calculation results and with the data obtained using laser shock waves.
Experimental estimates of the process of the ejection of particles and the formation of plasma during the shock wave exits on the free surface of the cooper sample studied were carried out. The ...radiation intensity was recorded by a three-channel pulsed pyrometer in an experimental assembly with lateral observation. When the impactor speed was about 5 km/s, a stream of particles and plasma flew from the target surface, the front speed of which reached 12.5 km/s.
The experimental results showing the formation features of a cylindrical detonation wave with a multipoint initiation are presented in this work. One of the main features of the process is the ...presence of the "nodes" on the detonation wave, i.e. points of convergence of detonation waves from the neighbor points of initiation. The other feature is the presence of the "bundles" which are exeunt to the detonation products. Nodes are the points with high energy level at detonation front. They may cause hydrodynamic instabilities during the compression of a metal liner. Parietal flows in the cell structure of detonation products may be reason for formation of "bundles". It should be noted that the detonation wave is always convex between the neighbor "nodes", although in the initial moment the triple-wave Mach configuration is forming and it should lead to aligning of cylindrical wave. The experiments with the use of high explosives with different densities (from 0.95 to 1.65 g/cm3) were carried out on the laboratory installation. The characteristic features of the detonation wave formed by the multipoint initiation can be seen both in solid and in liquid high explosives. Different design features (interlayers made of different materials etc.) did not lead to disappearing of "bundles" and smoothing of "nodes" at the detonation wave.
One method of studying materials or plasma under pressure pulse loading is axisymmetric compression using a convergent cylindrical detonation wave. Such waves are often generated by multipoint ...initiation and have a number of specific features that may affect the properties of the test objects. To solve specific problems, it is proposed to use a laboratory explosive system based on a converging cylindrical detonation wave with 12–48 initiation points. The TNT equivalent of the charge is less than 1 kg. The main method of research is visualization using a domestic high-speed Nanogeit camera with a nanosecond time resolution. The structure of the converging detonation wave is shown, and its velocity along the radius is determined. It is shown that for a charge of limited thickness, the curvature of the detonation wave front for various explosives depends only on the distance to the initiation point.
In this paper, the authors show the possible way of registration of the microparticles and plasma jets escaping from the inner surface of metal cylindrical liner when the detonation wave reaches it. ...The liner is allocated within experimental setup and is compressed by detonation products. Jets have been registered by Langmuir gauge which connection circuit was developed by the authors. The authors also developed a technique a method for detecting the signal under study. Average particle (about 4 km/s) and plasma (about 7 km/s) jet velocity is estimated by using the developed technique for copper liner compressed by detonation products. The results of this experiment correlate with those for plane setup.
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