bluuebunny/crossref_metadata_2025_split huggingface dataset:
High power test of the first C-band spherical pulse compressor prototype
Authors: Li Z. B. , Fang W. C. , Gu Q. , Tan J. H. , Huang X. X. , Zhao Z. T. 
Published: December 2019

Abstract
Recently, a new C-band (5712 MHz) compact spherical radio frequency (RF) pulse compressor was designed and tested for Shanghai Soft X-ray Free Electron Laser Facility (SXFEL). This pulse compressor utilizes one high Q0 spherical RF resonant cavity that works with two TE1,1,3 modes and a dual-mode polarized coupler. The peak power multiply factor is 6.1 and average power gain 3.8 in theory. During the high power test, a peak power multiply factor of 5.74 and average power gain of 3.77 was achieved. This paper presents the RF measurement of the C-band spherical pulse compressor and the high power test results.
Multipacting studies of the coaxial coupler for BNCT DTL
Authors: Fan M X , Liu H C , Li A H , Qu P H , Wang Y , Wu X L , Li B , Chen Q , Peng J , Wang A X , Fu S N 
Published: December 2019

Abstract
Multipacting is a phenomenon in which electrons grow sharply under certain conditions in a RF structure. It may lead to the breakdown or even damage to the equipment. Therefore, it is very important to calculate the Multipacting range in the RF equipment design. Since the phenomenon is too complicated to use the formula to fully predict it, numerical simulation is employed. There are many computer codes (such as Track3P, MultiPac, CST PS, etc.) used to simulate the phenomenon, but most of them are not commercial. In this paper, theories used in coaxial line for predicting multipacting are introduced; the CST PS is chosen to simulate the multipacting of coaxial coupler for BNCT DTL; finally, methods of suppressing multipacting are discussed.
Utilizing the high shunt impedance TM020-mode cavity in the double RF systems for the storage ring of the Thailand new light source
Authors: Juntong N , Phimsen T , Chulakham N , Malichan S 
Published: December 2019

Abstract
The utilization of the TM020-mode cavity for the storage ring based light source was pioneered by SPring-8 with its high quality factor and hence its high shunt impedance. KEK-LS has also studied the possibility of using this type of cavity for their storage ring. The TM020-mode cavity has larger transverse dimension compared to the traditional TM010-mode cavity, but with its higher shunt impedance it can be designed to fit in the new low emittance storage ring regardless. The new storage ring based light source project in Thailand aims to optimum the low emittance beam in nano-meters region with the energy of 3 GeV. The TM020-mode cavity was considered as the main cavity and the harmonic cavity for the storage ring. They have been designed to have their pipe aperture fits the storage ring beam ducts. The main cavity has a high shunt impedance of 8.3 MΩ with the 51,000 unloaded quality factor. The harmonic cavity has a high shunt impedance and an unloaded quality factor of 2.45 MΩ and 36,000, respectively. The damping mechanism of the parasitic modes and the tuning mechanism of the operating mode of these cavities were also studied. There will be four main cavities and six harmonic cavities in the new storage ring. Detailed design and study of these cavities will be presented.
Design of the elliptical superconducting cavities for the JAEA ADS
Authors: Yee-Rendon B , Kondo Y , Maekawa F , Meigo S , Tamura J 
Published: December 2019

Abstract
The superconducting CW proton linear accelerator for an Accelerator Driven Subcritical System (ADS) proposed by Japan Atomic Energy Agency (JAEA) employs elliptical cavities for the final acceleration of 180 MeV to 1.5 GeV. Since this energy region implies a changed of β from 0.55 to 1, two cavity models were developed using the geometrical betas of 0.68 and 0.89 to improve the acceleration efficiency. The study of the electromagnetic design was simulated using SUPERFISH (SF) code and python program to do variable scan, the results were benchmarked with CST Microwave Studio program (CST).
Is it possible to use additive manufacturing for accelerator UHV beam pipes?
Authors: Jenzer S. , Alves M. , Bilgen S. , Bonis J. , Brisset F. , Djelali S. , Gonnin A. , Guerrier M. , Grasset D. , Letellier-Cohen F. , Mercier B. , Mistretta E. , Sattonnay G. 
Published: December 2019

Abstract
Additive Manufacturing (AM) enables 3D metallic objects to be built by adding layer- upon-layer of material. This technology can be applied to produce Ultra High Vacuum components for particle accelerators. We investigated in this work the reproducibility of AM 316L stainless steel properties for different specimens supplied by several manufacturers with the same process. Microstructure and mechanical properties of AM samples depends on manufacturers: indeed, they are largely influenced by processing parameters, which produces heterogeneous and anisotropic microstructures that differ from traditional wrought counterparts. The outgassing rates of vacuum AM 316L tubes were determined and the secondary electron yield was also measured. Results are very promising to consider the use of AM to construct accelerator beam pipe components.
Optics Design and Beam Dynamics simulation for a VHEE Radiobiology beam line at PRAE accelerator
Authors: Han Y , Faus Golfe A , Vallerand C , Bai B , Duchesne P , Prezado Y , Delorme R , Poortmans P , Favaudon V , Fouillade C , Pouzoulet F , Dosanjh M 
Published: December 2019

Abstract
The Platform for Research and Applications with Electrons (PRAE) is a multidisciplinary R&D facility gathering subatomic physics, instrumentation, radiobiology and clinical research around a high-performance electron accelerator with beam energies up to 70 MeV. In this paper we report the complete optics design and performance evaluation of a Very High Energy Electron (VHEE) innovative radiobiology study, in particular by using Grid mini-beam and FLASH methodologies, which could represent a major breakthrough in Radiation Therapy (RT) treatment modality.
Simulation of collisionless shocks in plasmas with high metallicity
Authors: Kropotina J A , Levenfish K P , Bykov A M 
Published: December 2019

Abstract
The results of hybrid simulation of low-beta supercritical quasi-parallel shocks in high metallicity plasma are presented. The structure of upstream and downstream turbulence is addressed and velocities of the corresponding scattering centers are derived. It is shown that independently of their chemical composition the shocks experience self-reformation process. However, the period of self-reformation as well as the wave spectrum is greatly affected by the presence of substantial admixture of weakly charged heavy ions. Also the downstream magnetic field amplification is stronger for the high metallicity case.
r-modes in stratified neutron stars with entrainment
Authors: Kantor E M , Dommes V A , Gusakov M E 
Published: December 2019

Abstract
We calculate the temperature-dependent r-mode spectrum of superfluid neutron stars with npeµ (neutron, proton, electron, muon) core composition. This study is an extension of the previous work by Kantor, Gusakov [MNRAS 469, 3928 (2017)], where such spectrum was calculated under simplifying assumption of vanishing entrainment between superfluid neutrons and superconducting protons. We show that accounting for the entrainment leads to non-analytic behavior of the spectrum at small rotation rates. Namely, we find that in the leading order in rotation accounting for any non-zero value of entrainment eliminates superfluid r-modes. We show that next-to-leading order in rotation restores the superfluid r-modes in the spectrum. We calculate this spectrum and show that for certain neutron star models normal r-mode experiences stabilizing resonances with superfluid r-modes. This confirms the scenario of Gusakov, Chugunov, and Kantor [PRL 112, 151101 (2014)] that explains neutron stars in low-mass X-ray binaries.
Wolf-Rayet stars in young massive star clusters as potential sources of Galactic cosmic rays
Authors: Kalyashova M E , Bykov A M , Osipov S M , Ellison D C , Badmaev D V 
Published: December 2019

Abstract
For most elements, the isotopic ratios seen in cosmic rays (CRs) are similar to those in the solar wind. The most important exception to this is 22Ne/20Ne where the CR value is ∼ 5 times that of the solar wind. According to most recent models of nucleosynthesis, a large amount of 22Ne is generated in Wolf-Rayet (WR) stars. In the winds of carbon sequence of WR stars, i.e., WC stars, the isotopic ratio 22Ne/20Ne can be much larger than in the solar wind. Here, we consider CRs produced by 22Ne-enriched WR winds in young massive star clusters assuming the acceleration occurs from an ensemble of shock waves from the massive stars’ winds. We estimate the fraction of all Galactic CRs such sources may produce for a given set of parameters.
Equation of state and composition of the inner crust of an accreting neutron star: multicomponent model
Authors: Shchechilin N N , Chugunov A I 
Published: December 2019

Abstract
Correct interpretation of X-ray observations of transiently accreting neutron stars requires modeling of nuclear-physical processes in these objects. We consider a chain of nuclear reactions that drives the crust composition in an accreting neutron star and heats up the star. We constructed multicomponent approach with the kinetics of nuclear reactions described in simplified stepwise manner. The redistribution of nucleons between nuclei by emission and capture of neutrons is shown to significantly affect the nuclear reaction chains and the composition of the inner crust. In particular, even if the outer crust has one-component composition, the appearance of free neutrons in the inner crust leads to branching of reaction chains and formation of the multicomponent composition. We apply the compressible liquid drop nuclear model, which includes effects of free neutrons on nuclear energies. It allows us to calculate the composition, the heating profile and the equation of state of matter up to densities ρ ≃ 2 × 1013 g cm−3.
Chandra measurements of the proper motion of the γ-ray pulsar J0633+0632
Authors: Danilenko A A , Karpova A V , Shibanov Yu A 
Published: December 2019

Abstract
We measured the proper motion of a γ-ray radio-quiet pulsar J0633+0632 using Chandra observations performed in 2009 and 2017. The measured proper motion is 53 ± 15 mas yr−1. We found that the proper motion direction does not follow the extension of the J0633+0632 pulsar wind nebula. The J0633+0632 pulsar wind nebula therefore can be a jet-like feature or a misaligned outflow. We also discuss a possible birth cite of the pulsar.
Analysis of the surfaces and gravitational fields of planets using robust modeling methods
Authors: Demina N Y , Andreev A O , Nefedyev Y A , Akhmedshina E N , Demin S A 
Published: December 2019

Abstract
The work focuses on the development of methods and algorithms for the simulation of celestial bodies’ dynamic and static states. There are 2 types of models: global and local ones. The creation of local simulation models (LSM) is complicated as the emergent properties of the system are getting lost. Nevertheless, LSM are of great importance when analyzing planetology processes. When areas are covered with reference points unevenly and the distance between them increases, the method used in the work provides the higher accuracy of model forecasting compared to the use of interpolation formulas. LSM allow investigating both the whole planetary system and its local parts and are aimed at the predictive determination of topographic, gravimetric, and magnetic parameters.
Jeans smoothing of the Ly forest absorption lines
Authors: Telikova K N , Balashev S A , Shternin P S 
Published: December 2019

Abstract
We investigate a contribution of the Jeans smoothing to the minimal width of Ly forest lines and discuss how the accounting for this additional broadening affects the inferred parameters of the intergalactic matter equation of state. We estimate a power-law index γ of the equation of state, a temperature at the mean density T
0 and a hydrogen photoionization rate Γ within 4 redshift bins. Furthermore, in each bin we obtain an upper limit on the scale-parameter f
J, which sets the relation between the Jeans length and the characteristic physical size of the absorber clouds.
Two tori of the Vela pulsar wind nebula
Authors: Ponomaryov G A , Levenfish K P , Petrov A E 
Published: December 2019

Abstract
In the frame of the axisymmetric relativistic magnetohydrodynamic simulations we show that the double-arc feature of the Vela pulsar wind nebula (PWN) visible in soft X-rays can be reproduced at high inclination (obliquity) of the Vela pulsar and low magnetization of its wind provided the turbulent and magnetic energies of the nebula dissipate effectively. In that case, the arcs represent the Doppler brightened regions of two persistent large-scale toroidal whirls of strongly magnetized plasma located below and above the wide low-magnetized equatorial belt of the nebula. If the long-term persistence of the large-scale magnetic structures would be confirmed in more realistic simulations, the difference in X-ray morphology of the Crab and Vela PWNe can be explained by the difference in spin-down and inclination of their parent pulsars, and not by the very different magnetization of their winds, as supposed earlier.
X-ray of the 2017 September 10 Solar Flare
Authors: Ovchinnikova E P , Charikov Yu E , Shabalin A N 
Published: December 2019

Abstract
The analysis of soft and hard X-ray radiation of behind the limb solar flare SOL2017-09-10T15:35 according to the RHESSI data was carried out. The plasma parameters were determined: emission measure, temperature, density. Sources of hard X-ray radiation >30 keV are observed for several hours after the maximum of the flare. It indicates the long-term processes of acceleration of electrons in the solar corona. The rise of the X-ray source during 6.5 hours was ∼70 arcsec. It was proposed also an alternative method for determining the plasma density, based on cross-correlation analysis of time series (time delay method).
R-mode stabilization in neutron stars with hyperon cores
Authors: Ofengeim D D , Gusakov M E , Haensel P , Fortin M 
Published: December 2019

Abstract
R-mode oscillations of neutron stars are known to be generally unstable with respect to the emission of gravitational waves. This instability can be suppressed by dissipative processes in the neutron star core. The standard minimal nucleonic model of the core cannot stabilize r-modes for many observed neutron stars, at the same time the probability to observe them unstable should be very low. One of the solutions to this problem is to account for possible presence of hyperons in the stellar core. Hyperons strongly enhance bulk viscosity in the core, which effectively suppresses the r-mode instability. We revisit the bulk viscosity calculations in the non-superfluid hyperon matter and briefly discuss the effect of baryon superfluidity. Our results suggest that the hyperon solution to the r-mode problem is more promising than it was thought before.
The cold neutral phase of the interstellar medium in high redshift galaxies
Authors: Balashev S A , Klimenko V V , Noterdaeme P , Krogager J K , Ledoux C , Ivanchik A V , Varshalovich D A , Petitjean P 
Published: December 2019

Abstract
We present the results of spectroscopic analysis of seven new H2-bearing damped Ly- systems in redshift range z=2.5 − 3. These systems were originally selected from SDSS catalog using a direct search for H2 and followed up with X-SHOOTER spectrograph at 8-m Very Large Telescope observatory. We measured the column densities of HI, H2 on various rotational levels, and metals species in different ionization stages and excitation levels. We used the rotational excitation of H2 molecules together with the fine-structure levels of neutral carbon to constrain the physical conditions in the associated medium. We found typical values for the kinetic temperature T ∼ 80 − 120 K, hydrogen density n
H
∼ 30 − 400 cm−3 and UV radiation field ξUV
∼ 0.4 − 5 times of the Draine field. These values along with estimated thermal pressure are in agreement with expected values from the theoretical calculation of the cold neutral interstellar medium.
Kerr black hole shadow: non-parametric description and analytic methods of spin extraction
Authors: Kraav Kirill 
Published: December 2019

Abstract
In this paper we study the asymmetry of the shadow cast by a rotating Kerr black hole. Using Bardeen parametric formulas we plot contours of black hole shadows for different values of black hole’s angular momentum and different observer’s positions. In the case of the equatorial observer we present an equation that explains the behaviour of the numeric Hioki-Maeda curve, which is used to measure the black hole angular momentum from it’s shadow. Also in this case we introduce a new observable of the shadow and derive a simple formula that allows to constrain the black hole spin via measuring this observable. Finally we come out with the formula that provides the non-parametric description of the black hole shadow.
Influence of non-gravitational effects on the orbits of a few potentially hazardous asteroids
Authors: Martyusheva A 
Published: December 2019

Abstract
Observations of Mars and Venus-crossing asteroid (5131) 1990 BG and the near-Earth approaching asteroid (13553) Masaakikoyama 1992 JE were made using ZA-320M and MTM-500M telescopes of the Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo. Evolution of their orbits was investigated taking into account the Yarkovsky effect, as well as the solar radiation pressure influence for various values of albedo of these objects. The obtained results were summarized and compared with results of the Yarkovsky effect for (308635) 2005 YU55, (418094) 2007 WV4, 2017 VR12 and (276033) 2002 AJ129, which had been studied earlier. Conclusions about non-gravitational effects on the motion of potentially hazardous asteroids were drawn.
Geophysical effects of solar activity: long-term variations in occurrences of magnetic storms with sudden and gradual commencements
Authors: Veretenenko S , Ogurtsov M , Obridko V 
Published: December 2019

Abstract
Magnetic storms with sudden and gradual commencements are related to different agents of solar activity and form two independent populations. Coronal mass ejections which are more frequently related to active regions on the Sun (local magnetic fields with closed configuration) give rise, as a rule, to magnetic storms with sudden commencements. High-speed streams of solar wind related to solar coronal holes (regions of magnetic fields with open configuration) give rise to magnetic storms with gradual commencements. In this work we studied annual occurrences of magnetic storms with sudden and gradual commencements on the base of the data from IZMIRAN and Slutsk (Pavlovsk) magnetic observatories for the period 1878-2015, the correlation and spectral analysis being used. It was found that the occurrences of large and moderate magnetic storms with gradual commencements are characterized by long-term variations at the multidecadal and secular time scales. Wavelet spectra of occurrences of these storms reveal a dominant periodicity of ∼36 years (close to the Brückner cycle) and less pronounced ∼60-year and ∼90-year periodicities on the entire time interval under study. It was found that ∼11-year variations in occurrences of storms with gradual commencements were the most statistically significant in ∼1900-1920 and ∼1980-2000, but they were not observed in ∼1940-1960. The occurrence of magnetic storms with sudden commencements is characterized by a dominant ∼11-year periodicity almost on the entire interval of observations, whereas long-term variations are less pronounced. The obtained results provide evidence for a different time evolution of global and local solar magnetic fields.
The X-ray polarimeter of solar flares for the Interhelioprobe mission: a study of the characteristics of the physical model using radioisotope radiation sources
Authors: Savchenko M I , Kruglov E M , Lazutkov V P , Skorodumov D V , Shishov I I 
Published: December 2019

Abstract
The paper describes the physical model of the PING-P polarimetry unit of the PING-M X-ray polarimeter. The polarimeter is developed jointly by the Ioffe Institute and the Institute of Astrophysics of the Moscow Engineering Physics Institute for the Interhelioprobe mission. The model (PING-P-FM), made by the Ioffe Institute, represents the detector part of the polarimeter. The polarization degree is determined by the measurement of the asymmetry of the scattered radiation field. The device uses active scatterers based on paraterphenyl crystals for detecting the events of Compton scattering. A useful signal is the coincidence of pulses from one of the active scatterers (detector-scatterer) and one detector-receiver of scattered radiation. The polarimetry unit contains 3 detector-scatterers and 6 detector-receivers, thus resulting in 18 measurement channels. The requirements for instrument symmetry and stability of the measuring channels are high. The paper presents the results of an experimental study of the parameters of the measuring channels of the PING-P-FM model and their calibrations at different X-ray energies using Cd-109, Am-241, and Ba-133 isotope sources.
Gamma-ray lines in solar flares with proton spectra measured by PAMELA experiment
Authors: Lysenko A L , Bogomolov E A , Vasiliev G I , Ovchinnikova E P 
Published: December 2019

Abstract
During the solar flares protons and heavier ions are accelerated up to GeV energies. Accelerated ions can escape the Sun and be registered directly on spacecraft or penetrate into the solar atmosphere and then produce gamma-ray lines as the result of nuclear reactions. Previous studies revealed very poor correlation between fluxes of interplanetary ions and gamma-ray line emission. In this work we focus on joint observations of interplanetary solar energetic particles registered by PAMELA experiment and gamma-ray emission registered by Konus-Wind instrument in hard X-ray and soft gamma-ray ranges. This study confirmed the previous results: during the period from 2006 to 2014 there were only two solar flares registered both by PAMELA and Konus-Wind at energies above 1 MeV. We analyze gamma-ray spectrum for one of these flares and make suggestions about the reasons for the low correlation between interplanetary solar accelerated ions and accelerated ions interacted in the solar atmosphere.
Analysis of the dynamic coordinate system using photoelectric lunar occultations
Authors: Churkin K O , Andreev A O , Nefedyev Y A , Mubarakshina R R , Borovskih V S 
Published: December 2019

Abstract
In this work we propose the determination of the astrophysical dynamic coordinate system’s orientation in relation to HCRF (Hipparcos Celestial Reference Frame) using photoelectric lunar occultation. The photoelectric method of recording an occultation that allows obtaining occultations moment with the accuracy up to 0.001s (i.e. 100 times more accurate than by visual method) was found to be the most accurate. Apart from the tasks of space geodesy, photoelectric observations allow carrying out other interesting researches, too. These tasks include determination of amendments to orbital longitude and latitude of the Moon and amendments to ephemeris time. The photoelectric observations of occultation are valuable materials for solving some astrophysical tasks. If one records changes in magnitude at the moment when a star is occultated by the Moon, then one may obtain diameter of the occultated star through the spectrum of those changes. Other important problems are detecting double and multiple systems of stars and measuring angular distances between their components.