Transition radiation of fast electrons as a broadband vacuum-ultraviolet radiation source

The characteristics of a possible radiation source in the vacuum ultraviolet and soft X ray range based on the transition radiation of electrons with an energy of about 100 keV are calculated. The possibilities of enhancing the radiation yield in the geometry of the glancing interaction of electrons with a target are ana lyzed. The possibility of creating a source with a yield on the order of 10–5 photon/(eV sr) per electron is dem onstratedyesBelgorod State National Research Universit

Правоотношение и нравственность: современное осмысление и новые подходы

The subject of the article is the views of prof. P.P. Serkov and other domestic legal scientists on the problems of legal relations and its moral component from the standpoint of a lawyerresearcher. The article considers theoretical and methodological aspects of the doctrine of legal relationships, the content, patterns of the emergence and development of elements of the mechanism of legal relationships, the problems of classification of legal relationships, debatable issues of general regulatory legal relationships. Particular attention is paid to the analysis of approaches and theoretical provisions related to understanding the complex type of complex legal relationship.The purpose of the study is to confirm the scientific hypothesis of P.P. Serkov about the mechanism of legal relationship from the point of view of its relation with issues of morality, social aspects of subjective and social life, as well as to formulate conceptual ideas and specific proposals for improving the mechanism of complex legal relationship and its part, the mechanism of corporate and ethical legal relationship in the sphere of advocacy.Methodology and methods. The research methodology is based on the dialectical method, which made it possible to consider the judgments of scientists in development with existing contradictions and relations with new phenomena in law enforcement. The article also uses methods of analysis and synthesis, deduction and induction, modeling and extrapolation, formal legal and comparative legal method.The main results, scope of the application. The scientific and practical validity of the doctrine of the legal relationship mechanism created by P.P. Serkov is shown in the article. The presence of a moral component in each act of legal regulation, as well as the significance of the scholar's ideas and hypotheses in expanding the possibilities of general theoretical and sectoral research in this area and creating conditions for improving law-making and law enforcement practice are brought into light.Conclusions. The direction of development of the mechanism of complex legal relationship has been substantiated and specific proposals have been formulated to improve its part the mechanism of corporate and ethical legal relationship in the field of the legal profession.Предпринимается попытка поиска направлений развития концепции механизма правоотношения и его нравственного компонента на основе анализа взглядов П.П. Серкова, изложенных в монографиях «Правоотношение (Теория и практика современного правового регулирования)» (М.: Норма, 2018) и «Правоотношение (Нравственность современного правового регулирования)» (М.: Норма, 2020), с учетом иных суждений отечественных ученых. Формулируются концептуальные идеи и конкретные предложения по совершенствованию механизма комплексного правоотношения и его части – механизма корпоративного профессионально-этического правоотношения в сфере адвокатской деятельности и адвокатуры

On the Interpretation of Diamagnetic Loop Measurements for a Current-Carrying Plasma Column in a Conducting Chamber

A general expression is derived for the signal of a magnetic loop encircling a plasma column inside a conducting chamber with nonuniform current distribution over the plasma cross-section. The ratio of the paramagnetic component to the diamagnetic component of the signal is shown to be independent of the loop radius. Both components increases the loop radius decreases from the chamber radius to the plasma radius. From the derived expressions, the paramagnetic component of the signal is calculated numerically for several current distributions including those of interest for the experiments. At a given total current, the paramagnetic component of the signal may vary considerably, which generally has to be taken into account in interpreting experimental data. The results of the calculations are used to process the data obtained in the experiments on the SPIN plasma device

Spatiotemporal Evolution of Runaway Electron Momentum Distributions in Tokamaks

Novel spatial, temporal, and energetically resolved measurements of bremsstrahlung hard-x-ray (HXR) emission from runaway electron (RE) populations in tokamaks reveal nonmonotonic RE distribution functions whose properties depend on the interplay of electric field acceleration with collisional and synchrotron damping. Measurements are consistent with theoretical predictions of momentum-space attractors that accumulate runaway electrons. RE distribution functions are measured to shift to a higher energy when the synchrotron force is reduced by decreasing the toroidal magnetic field strength. Increasing the collisional damping by increasing the electron density (at a fixed magnetic and electric field) reduces the energy of the nonmonotonic feature and reduces the HXR growth rate at all energies. Higher-energy HXR growth rates extrapolate to zero at the expected threshold electric field for RE sustainment, while low-energy REs are anomalously lost. The compilation of HXR emission from different sight lines into the plasma yields energy and pitch-angle-resolved RE distributions and demonstrates increasing pitch-angle and radial gradients with energy.United States. Department of Energy (DE-FC02-04ER54698)United States. Department of Energy (DE-FG02-07ER54917)United States. Department of Energy (DE-AC05-00OR22725)United States. Department of Energy (DE-FC02-99ER54512)United States. Department of Energy (DE-SC0016268

A novel path to runaway electron mitigation via deuterium injection and current-driven MHD instability

Relativistic electron (RE) beams at high current density (low safety factor, q ( a )) yet very low free-electron density accessed with D-2 secondary injection in the DIII-D and JET tokamak are found to exhibit large-scale MHD instabilities that benignly terminate the RE beam. In JET, this technique has enabled termination of MA-level RE currents without measurable first-wall heating. This scenario thus offers an unexpected alternate pathway to achieve RE mitigation without collisional dissipation. Benign termination is explained by two synergistic effects. First, during the MHD-driven RE loss events both experiment and MHD orbit-loss modeling supports a significant increase in the wetted area of the RE loss. Second, as previously identified at JET and DIII-D, the fast kink loss timescale precludes RE beam regeneration and the resulting dangerous conversion of magnetic to RE kinetic energy. During the termination, the RE kinetic energy is lost to the wall, but the current fully transfers to the cold bulk thus enabling benign Ohmic dissipation of the magnetic energy on longer timescales via a conventional current quench. Hydrogenic (D-2) secondary injection is found to be the only injected species that enables access to the benign termination. D-2 injection: (1) facilitates access to low q ( a ) in existing devices (via reduced collisionality & resistivity), (2) minimizes the RE avalanche by 'purging' the high-Z atoms from the RE beam, (3) drives recombination of the background plasma, reducing the density and Alfven time, thus accelerating the MHD growth. This phenomenon is found to be accessible when crossing the low q ( a ) stability boundary with rising current, falling toroidal field, or contracting minor radius-the latter being the expected scenario for vertically unstable RE beams in ITER. While unexpected, this path scales favorably to fusion-grade tokamaks and offers a novel RE mitigation scenario in principle accessible with the day-one disruption mitigation system of ITER

Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

Tritium distributions on W-coated divertor tiles used in the third JET ITER-like wall campaign

Tritium (T) distributions on tungsten (W)-coated plasma-facing tiles used in the third ITER-like wall campaign (2015–2016) of the Joint European Torus (JET) were examined by means of an imaging plate technique and β-ray induced x-ray spectrometry, and they were compared with the distributions after the second (2013–2014) campaign. Strong enrichment of T in beryllium (Be) deposition layers was observed after the second campaign. In contrast, T distributions after the third campaign was more uniform though Be deposition layers were visually recognized. The one of the possible explanations is enhanced desorption of T from Be deposition layers due to higher tile temperatures caused by higher energy input in the third campaign