Influence of misalignments on performance of externally occulted solar coronagraphs. Application to PROBA-3/ASPIICS

ASPIICS is a novel externally occulted coronagraph that will be launched onboard the PROBA-3 mission of ESA. The external occulter (EO) will be placed on one satellite ~150 m ahead of the second satellite with an optical instrument. During part of each orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the EO and the primary objective will allow observations of the white-light solar corona starting already from ~1.1RSun. We analyze influence of shifts of the satellites and misalignments of optical elements on diffracted light. Based on the quantitative influence of misalignments on diffracted light, we will provide a "recipe" for choosing the size of the internal occulter (IO) to achieve a trade-off between the minimal height of observations and sustainability to possible misalignments. We implement a numerical model of the diffracted light and its propagation through the optical system, and compute intensities of diffracted light throughout the instrument. Our numerical model extends axi-symmetrical model of Rougeot et al. 2017 to non-symmetrical cases. The computations fully confirm main properties of the diffracted light obtained from semi-analytical consideration. Results: relative influences of various misalignments are significantly different. We show that: the IO with R=1.1RSun is large enough to compensate possible misalignments in ASPIICS, apodizing the edge of the IO leads to additional suppression of the diffracted light. Conclusions: the most important misalignment is the tilt of the telescope WRT the line connecting the center of the EO and the entrance aperture. Special care should be taken to co-align the EO and the coronagraph, i.e. co-aligning the diffraction fringe from the EO and the IO. We suggest that the best orientation strategy is to point the coronagraph to the center of the EO.Comment: 13 pages, 15 figure

Modeling and removal of optical ghosts in the PROBA-3/ASPIICS externally occulted solar coronagraph

Context: ASPIICS is a novel externally occulted solar coronagraph, which will be launched onboard the PROBA-3 mission of the European Space Agency. The external occulter will be placed on the first satellite approximately 150 m ahead of the second satellite that will carry an optical instrument. During 6 hours per orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the external occulter and the primary objective will allow observations of the white-light solar corona starting from extremely low heights 1.1RSun. Aims: To analyze influence of optical ghost images formed inside the telescope and develop an algorithm for their removal. Methods: We implement the optical layout of ASPIICS in Zemax and study the ghost behaviour in sequential and non-sequential regimes. We identify sources of the ghost contributions and analyze their geometrical behaviour. Finally we develop a mathematical model and software to calculate ghost images for any given input image. Results: We show that ghost light can be important in the outer part of the field of view, where the coronal signal is weak, since the energy of bright inner corona is redistributed to the outer corona. However the model allows to remove the ghost contribution. Due to a large distance between the external occulter and the primary objective, the primary objective does not produce a significant ghost. The use of the Lyot spot in ASPIICS is not necessary.Comment: 14 pages, 13 figure

State of the Hemostatic System in the Newborn Calves with Diverse Birth Weights

The studies on the peculiarities of hemostatic indices in calves (n=250) of Holstein- Friesian breed with diverse birth weights were conducted under the conditions of a dairy farm with the aid of generally accepted clinical, instrumental and laboratory methods. The research has demonstrated that in comparison with the adults the newborns weighing from 36.5 to 29 kg revealed a diversity of hemostatic indices but generally there was a functionally acceptable balance of its links without a tendency to coagulopathy or thrombosis. Fetal growth restriction in cattle with low birth weight has a significant effect on the hemostatic system. Insufficient weight of more than 7 % provokes hypercoagulability syndrome which is caused by increased levels of adrenalin, toxic products of impaired metabolism and destruction of erythrocyte membranes. The newborns with lower weight demonstrated signs of primary coagulopathy conditioned by functional inferiority of the organs in which the synthesis of coagulation factors occurred that led to the development of disseminated intravascular coagulation. The revealed dependence of the hemostatic disorders evidence on the severity of weight insufficiency indicates coagulopathy, emerging in epigenetics of the main pathology after primary damage and conditioning the severity of the newborns’ state, as one of the main mechanisms of hypotrophy pathogenesis

Binding energy constraint on matter radius and soft dipole excitations of C-22

An unusually large value of the C-22 matter radius has recently been extracted from measured reaction cross sections. The giant size can be explained by a very loose binding that is, however, not known experimentally yet. Within the three-body cluster model we have explored the sensitivity of the s-motion-dominated C-22 geometry to the two-neutron separation energy. A low energy of a few tens of keV is required to reach the alleged experimental lower value of the matter radius, while the experimental mean radius requires an extremely tiny binding. The dependence of the C-22 charge radius on the two-neutron separation energy is also presented. The soft dipole mode in C-22 is shown to be strongly affected by the loose binding and should be studied in the process of Coulomb fragmentation

Modified variable phase method for the solution of coupled radial Schrodinger equations

A modified variable phase method for the numerical solution of coupled radial Schrodinger equations, which maintains linear independence for different sets of solution vectors, is suggested. The modification involves rearrangement of coupled equations to avoid the usual numerical instabilities associated with components of the wave function in their classically forbidden regions. The modified method is applied to nuclear structure calculations of halo nuclei within the hyperspherical harmonics approach

From Coulomb excitation cross sections to non-resonant astrophysical rates in three-body systems: 17^{17}Ne case

Coulomb and nuclear dissociation of $^{17}$Ne on light and heavy targets are studied theoretically. The dipole E1 strength function is determined in a broad energy range including energies of astrophysical interest. Dependence of the strength function on different parameters of the $^{17}$Ne ground state structure and continuum dynamics is analyzed in a three-body model. The discovered dependence plays an important role for studies of the strength functions for the three-body E1 dissociation and radiative capture. The constraints on the $[s^2]/[d^2]$ configuration mixing in $^{17}$Ne and on $p$-wave interaction in the $^{15}$O+$p$ channel are imposed based on experimental data for $^{17}$Ne Coulomb dissociation on heavy target.Comment: 12 pages, 13 figure

Assessment of Threats to the Security of the Cryptographic Authentication Mechanisms of the Monitor Devices of Vehicles

In accordance with the legislation on transport security, a number of vehicles must be equipped with on-Board control devices containing a cryptographic means of authentication, registration and storage of control data, including key information of the electronic signature. This paper presents a solution to the problem of justification of the adequacy of measures to counter known attacks and methods of discrediting the suggested cryptographic mechanisms and the corresponding protocol, drawn up in the form of a draft national standard and presented in the previous work of the authors devoted to study of its security properties. The solution presented is limited to the consideration of attacks divided into two large classes: passive and active attacks, including temporary attacks based on the study of the response time of one or more participants of the protocol. The analysis of the security threat model of the Protocol generating a common key with the authentication of subscribers intended for use in tachographs installed on vehicles shows that the protocol provides sufficient measures to counter known attacks. The found possible attacks are of a formal nature, not allowing the offender to obtain any additional information in order to discredit the protocol

Модель балансування паралельної обробки фото- відеокадрів в обчислювальному кластері для БПЛА

In solving some problems that are common to the system of operating UAVs, for example, parallelprocessing tasks of photo and video-frames, it seems appropriate the operative design of the computing cluster for UAV. The computing cluster for UAV is characterized by a dynamic structure(field) telecommunication system. This circumstance makes it necessary, for management purposes, tosynthesize such model of the cluster what allows, on the one hand, to calculate the effective plan forthe organization of the computation process, and on the other hand - to spend on these calculationsthe minimum resources (particularly - time). It is proposed, in the case of cluster for UAV, the classic,with criteria "cost - performance", (linear) V.Leontyev’s model. Figs:2. Refs:3 titles.При решении некоторых проблем, общих для системы действующих БПЛА, например задач параллельной обработки фото и видеокадров, представляется целесообразным оперативное проектирование вычислительного кластера для БПЛА. Вычислительный кластер для БПЛА характеризуется динамической структурой (полевой) телекоммуникационной системы. Это обстоятельство делает необходимым, для целей управления, синтезировать такую модель кластера, которая позволяет, с одной стороны, вычислить эффективный план организации вычислительного процесса, а с другой - затратить на эти вычисления минимальные ресурсы (вчастности - время). Предлагается, в случае кластера для БПЛА, модель в терминах «стоимость - производительность» на основе (линейной) модели В. Леонтьева. Рис.2. Библиогр.:3назв.При розв’язанні деяких проблем, загальних для системи діючих БПЛА, наприклад завданьпаралельної обробки фото і відео кадрів, представляється доцільним оперативне проектування обчислювального кластера для БПЛА. Обчислювальний кластер для БПЛА характеризується динамічною структурою (польової) телекомунікаційної системи. Ця обставина робить необхідним для цілей управління синтезувати таку модель кластера, яка дозволяє,з одного боку, обчислити ефективний план організації обчислювального процесу, а з іншого -витратити на ці обчислення мінімальні ресурси (зокрема - час). Пропонується, у випадку кластера для БПЛА, класична модель за критерієм «вартість - продуктивність» на основі(лінійної) моделі В. Леонтьєва. Рис.2. Бібліогр.:3 наз

Visibility of prominences using the He i D3 line filter on PROBA-3/ASPIICS coronagraph

We determine the optimal width and shape of the narrow-band filter centered on the He i D3 line for prominence and coronal mass ejection (CME) observations with the ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun) coronagraph onboard the PROBA-3 (Project for On-board Autonomy) satellite, to be launched in 2020. We analyze He i D3 line intensities for three representative non-local thermal equilibrium prominence models at temperatures 8, 30, and 100 kK computed with a radiative transfer code and the prominence visible-light (VL) emission due to Thomson scattering on the prominence electrons. We compute various useful relations at prominence line-of-sight velocities of 0, 100, and 300 km s−1 for 20 Å wide flat filter and three Gaussian filters with a full-width at half-maximum (FWHM) equal to 5, 10, and 20 Å to show the relative brightness contribution of the He i D3 line and the prominence VL to the visibility in a given narrow-band filter. We also discuss possible signal contamination by Na i D1 and D2 lines, which otherwise may be useful to detect comets. Our results mainly show that i) an optimal narrow-band filter should be flat or somewhere between flat and Gaussian with an FWHM of 20 Å in order to detect fast-moving prominence structures, ii) the maximum emission in the He i D3 line is at 30 kK and the minimal at 100 kK, and iii) the ratio of emission in the He i D3 line to the VL emission can provide a useful diagnostic for the temperature of prominence structures. This ratio is up to 10 for hot prominence structures, up to 100 for cool structures, and up to 1000 for warm structures

Development of High Granulated Straw Chambers of Large Sizes

We have developed the baseline design for the straw drift tube tracking detectors for high rate environment application. The low-mass inner straw elements and the technology of the multianode straws assembly was devised and checked. The prototype chamber was constructed and studied the granularity of similar chambers can be reduced to one cm2. Submitted to Physics of Elementary Particles and Atomic Nuclei, LettersComment: 6 pages, 10 figure