Astrobiological Constraints on Astrophysics

Life exists in the universe and therefore the astrophysical properties of the universe must be such that they allow the origin of life. We connect astrobiology and astrophysics via one astrobiological quantity—the probability of the origin of life. We show how this probability, if it is very low, will allow us to answer profound astrophysical questions such as the type of universe we live in, the fate of our universe, whether neutron stars, white and brown dwarfs evaporate and whether protons decay.

Nuclear Astrophysics Experiments in Collaboration with Ruhr University

This paper reports on two nuclear astrophysics experiments performed in collabora- tion with Ruhr University. In a 12C＋2C fusion reaction, the 12C（12C, a）20e and 12C（12C, p）23Na reactions were studied in the energy range of E = 2.10 MeV to 4.75 MeV using -y-ray spectroscopy. The deduced astrophysical S（E）＊ factor exhibited a new, strong resonance at E -= 2.14 MeV, which lay at the high-energy tail of the Gamow peak. The resonance increased the reaction rate of the ^-channel by a factor of five near T = 8 ~ l0s K. The electron screening in d（d, p）t was stud- ied for a series of deuterated metal, insulator and semiconductor targets. Compared with the measurements performed with a gaseous D2 target, a large effect was observed in most metals, while a comparatively small effect was found in the insulators and semiconductors. Subsequently the temperature dependence of the electron screening in the d（d, p）t reaction was studied for the deuterated metals Pt and Co. Enhanced electron screening decreased with increasing tempera- ture. These data represent the first observations of the temperature dependence of a nuclear cross section.

Chinese Journal of Astronomy and Astrophysics

An international bimonthly journal,founded in 2001 as a continuation of Acta Astrophysica Sinica(founded in 1981,ISSN 0253-2379).The Chinese Journal of Astronomy and Astrophysics (ISSN 1009-9271)is published for the Chinese Astronomical Society and the National Astronomical Observatories of Chinese Academy of Sciences by the Science Press in Beijing.

Optical Coherence in Astrophysics: The Powerful Alternative of Big Bang

The coherence of the interaction of light with a collisionless gas (Einstein 1917) founds the theory of gas lasers. It is, for the understanding of universe, a simpler and more powerful tool than the big bang which requires questionable supplements (dark matter, MOND, etc.). The Impulsive Stimulated Raman Scattering (ISRS) redshifts gradually light pulses which cross excited atomic hydrogen H*, so that the redshift is a measure of the column density of H*. Thus, the distance of the hot stars, surrounded by much H*, is exaggerated by the use of Hubble’s law. Local exaggerated distances create voids in the maps of galaxies which become spongy. The interpretation of spectra of quasars, the periodicity of galaxy redshifts introduce an experimental “Karlsson’s constant” exactly computed by ISRS. The need for dark matter comes from the exaggeration of the distance, therefore the size of galaxies. Without dark matter, celestial mechanics provides a reliable distance of spiral galaxies. Coherence also introduces superradiance and mode competition that explain that only the limbs of Stromgren spheres are visible as circles maybe punctuated by an even number of dots: Too numerous, the figures assigned to gravitational lenses can be such limbs. The coincidence of the ignition of the rings of SNR1987A with the extinction of the star is due to a multiphoton coherent scattering of star light, which amplifies the superradiant emission of the rings. A blueshift of microwaves crossing H* resulting, between 10 and 15 AU, of the expansion of solar wind, explains the “anomalous acceleration” of Pioneer probes. All is obtained without any change in theories of standard spectroscopy.

6-39 Motion Control for RIBLL1 Nuclear Astrophysics Experiment Terminal

The nuclear astrophysics experiments terminal of RIBLL1 (Radioactive Ion Beam Line in Lanzhou) is composed of two slide rails and a four-knife precision slit structure. Both of them are placed in a terminal chamber as shown in Fig. 1. During experiments, PPAC and experiment target are placed on two slide rails respectively. The width of four-knife slit is required to be adjusted during experiments. Also, in order to get results of different positions in chamber space, the position of PPAC and target must be able to be adjusted precisely in real time.

Recent progress in nuclear astrophysics research and its astrophysical implications at the China Institute of Atomic Energy

Nuclear astrophysics is a rapidly developing interdisciplinary feld of research that has received extensive attention from the scientifc community since the midtwentieth century.Broadly,it uses the laws of extremely small atomic nuclei to explain the evolution of the universe.Owing to the complexity of nucleosynthesis processes and our limited understanding of nuclear physics in astrophysical environments,several critical astrophysical problems remain unsolved.To achieve a better understanding of astrophysics,it is necessary to measure the cross sections of key nuclear reactions with the precision required by astrophysical models.Direct measurement of nuclear reaction cross sections is an important method of investigating how nuclear reactions infuence stellar evolution.Given the challenges involved in measuring the extremely low crosssections of nuclear reactions in the Gamow peak and preparing radioactive targets,indirect methods,such as the transfer reaction,coulomb dissociation,and surrogate ratio methods,have been developed over the past several decades.These are powerful tools in the investigation of,for example,neutron-capture(n,r)reactions with short-lived radioactive isotopes.However,direct measurement is still preferable,such as in the case of reactions involving light and stable nuclei.As an essential part of stellar evolution,these low-energy stable nuclear reactions have been of particular interest in recent years.To overcome the diffculties in measurements near or deeply within the Gamow window,the combination of an underground laboratory and high-exposure accelerator/detector complex is currently the optimal solution.Therefore,underground experiments have emerged as a new and promising direction of research.In addition,to better simulate the stellar environment in the laboratory,research on nuclear physics under laser-driven plasma conditions has gradually become a frontier hotspot.In recent years,the CIAE team conducted a series of distinctive nuclear astrophysics studies,relying on the Jinping Underground Nuclear Astrophysics platform and accelerators in Earth’s surface laboratories,including the Beijing Radioactive Ion beam Facility,as well as other scientifc platforms at home and abroad.This research covered nuclear theories,numerical models,direct measurements,indirect measurements,and other novel approaches,achieving great interdisciplinary research results,with high-level academic publications and signifcant international impacts.This article reviews the above research and predicts future developments.

从Research in Astronomy and Astrophysics的发展历程看期刊国际化的实现

以及Research in Astronomy and Astrophysics的发展历程的统计分析为例,解析如何实现中国科技期刊国际化。对其高被引论文做学科分布及学术特征分析,对于刊物各栏目的影响做比较分析,对于天文和天体物理的研究领域和方向做统计分析,总结该刊办刊的经验教训,提出期刊国际化的发展建议。

Research in Astronomy and Astrophysics的国际化发展实践

【目的】探索实现我国科技期刊国际化的途径,提供一些国际化办刊思路。【方法】以Research in Astronomy and Astrophysics(RAA)走向国际化的努力为例,重点介绍RAA建设国际化编委队伍、争取国际优秀稿源、实现国际化审稿,并在出版发行方面开展国际化合作等方面采取的一系列措施。【结论】RAA通过全方位的国际化努力,进一步扩大了期刊的宣传力,加强了期刊的影响力,从而提高了期刊的影响因子。

First result from the Jinping Underground Nuclear Astrophysics experiment JUNA:precise measurement of the 92 keV ^(25)Mg(p,γ)^(26)Al resonance

The ^(25)Mg(p,γ)^(26)Al reaction plays an important role in the study of cosmic 1.809 MeV γ-ray as a signature of ongoing nucleosynthesis in the Galaxy.At astrophysical temperature around 0.1 GK,the ^(25)Mg(p,γ)^(26)Al reaction rates are dominated by the 92 keV resonance capture process.We report a precise measurement of the 92 keV ^(25)Mg(p,γ)^(26)Al resonance in the day-one experiment at Jinping Underground Nuclear Astrophysics experiment(JUNA)facility in the China Jinping Underground Laboratory(CJPL).The resonance strength and ground state feeding factor are determined to be 3.8±0.3×10^(-10) eV and 0:660:04,respectively.The results are in agreement with those reported in the previous direct underground measurement within uncertainty,but with significantly reduced uncertainties.Consequently,we recommend new ^(25)Mg(p,γ)^(26)Al reaction rates which are by a factor of 2.4 larger than those adopted in REACLIB database at the temperature around 0.1 GK.The new results indicate higher production rates of ^(26g)Al and the cosmic 1.809 MeV γ-ray.The implication of the new rates for the understanding of other astrophysical situations is also discussed.

A novel multi-shot target platform for laser-driven laboratory astrophysics experiments

A new approach to target development for laboratory astrophysics experiments at high-power laser facilities is presented.With the dawn of high-power lasers,laboratory astrophysics has emerged as a field,bringing insight into physical processes in astrophysical objects,such as the formation of stars.An important factor for success in these experiments is targetry.To date,targets have mainly relied on expensive and challenging microfabrication methods.The design presented incorporates replaceable machined parts that assemble into a structure that defines the experimental geometry.This can make targets cheaper and faster to manufacture,while maintaining robustness and reproducibility.The platform is intended for experiments on plasma flows,but it is flexible and may be adapted to the constraints of other experimental setups.Examples of targets used in experimental campaigns are shown,including a design for insertion in a high magnetic field coil.Experimental results are included,demonstrating the performance of the targets.

Editorial review of HPLSE special issue on laboratory astrophysics

In 2018 the journal High Power Laser Science and Engineering produced a Special Issue on Laboratory Astrophysics.The scope of the special issue was to span the latest research and reviews on the following topics related to laboratory astrophysics and related phenomena.The topics invited for inclusion were:·collisionless shocks;·planetary formation dynamics and planetary interiors;·warm dense matter;·hydrodynamic and magnetohydrodynamic instabilities;·magnetic reconnection;·relativistic plasmas;·magnetic turbulence and magnetic amplification;·nuclear astrophysics;·radiative transfer and radiation hydrodynamics;·target design;·laser-based HED facilities.although this was not meant as an exhaustive list.As is usual with a special issue of this type Guest Editors were invited to lead in sourcing articles.

Laboratory astrophysics with laser-driven strong magnetic fields in China

In this paper, the recent studies of laboratory astrophysics with strong magnetic fields in China have been reviewed.On the Shenguang-II laser facility of the National Laboratory on High-Power Lasers and Physics, a laser-driven strong magnetic field up to 200 T has been achieved. The experiment was performed to model the interaction of solar wind with dayside magnetosphere. Also the low beta plasma magnetic reconnection(MR) has been studied. Theoretically, the model has been developed to deal with the atomic structures and processes in strong magnetic field. Also the study of shock wave generation in the magnetized counter-streaming plasmas is introduced.

Neutron and Alpha Structure in Neutron Deficient Nuclei in Astrophysics

The paper includes discussions on the important role of neutron and alpha configurations in proton-rich nuclei in nuclear astrophysics in terms of nucleosynthesis under extremely high-temperature hydrogenburning conditions. The νp-process, which is supposed to take place at the very early epoch of type II supernovae, has considerable neutrons and alphas together with protons. The alpha-induced reactions on proton-rich unstable nuclei in the light mass regions is expected to play a crucial role, but very few of them were investigated well yet because of the experimental difficulties. Specifically, I report our recent experimental effort for the breakout process from the pp-chain region,~7Be(α, γ)^(11)C(α,p)^(14)N under the νp-process. The neutron-induced reactions on proton-rich nuclei, which is even more a challenging subject, were investigated previously for very few nuclei. One possible experimental method is the Trojan Horse Method(THM). We successfully have applied THM to the ^(18)F(n,α)^(14)N reaction study with an unstable beam of ^(18)F.

Design and fabrication of gas cell targets for laboratory astrophysics experiments on the Orion high-power laser facility

This paper describes the design and fabrication of a range of ‘gas cell' microtargets produced by the Target Fabrication Group in the Central Laser Facility(CLF) for academic access experiments on the Orion laser facility at the Atomic Weapons Establishment(AWE). The experiments were carried out by an academic consortium led by Imperial College London. The underlying target methodology was an evolution of a range of targets used for experiments on radiative shocks and involved the fabrication of a precision machined cell containing a number of apertures for interaction foils or diagnostic windows. The interior of the cell was gas-filled before laser irradiation. This paper details the assembly processes, thin film requirements and micro-machining processes needed to produce the targets. Also described is the implementation of a gas-fill system to produce targets that are filled to a pressure of 0.1–1 bar. The paper discusses the challenges that are posed by such a target.

Direct measurement of the break-out ^(19)F(p,γ)^(20)Ne reaction in the China Jinping underground laboratory(CJPL)

Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in astrophysics.As one possible nucleosynthesis scenario,break-out from the hot carbon–nitrogen–oxygen(HCNO)cycle was thought to be the source of the calcium observed in these oldest stars.However,according to the stellar modeling,a nearly tenfold increase in the thermonuclear rate ratio of the break-out ^(19)F(p,γ)^(20) Ne reaction with respect to the competing ^(19)F(p,α)^(16) O back-processing reaction is required to reproduce the observed calcium abundance.We performed a direct measurement of this break-out reaction at the China Jinping underground laboratory.The measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass frame.The key resonance was observed at 225.2 keV for the first time.At a temperature of approximately 0.1 GK,this new resonance enhanced the thermonuclear ^(19)F(p,γ)^(20) Ne rate by up to a factor of≈7.4,compared with the previously recommended NACRE rate.This is of particular interest to the study of the evolution of the first stars and implies a stronger breakdown in their“warm”CNO cycle through the ^(19)F(p,γ)^(20) Ne reaction than previously envisioned.This break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.

The SLEGS beamline of SSRF

The Shanghai Laser Electron Gamma Source(SLEGS, located in BL03SSID) beamline at the Shanghai Synchrotron Radiation Facility(SSRF) is a Laser Compton Scattering(LCS) gamma source used for the investigation of nuclear structure, which is in extensive demand in fields such as nuclear astrophysics, nuclear cluster structure, polarization physics, and nuclear energy. The beamline is based on the inverse Compton scattering of 10640 nm photons on 3.5 GeV electrons and a gamma source with variable energy by changing the scattering angle from 20° to 160°. γ rays of 0.25-21.1 MeV can be extracted by the scheme consisting of the interaction chamber, coarse collimator, fine collimator, and attenuator. The maximum photon flux for 180° is approximately 10~7 photons/s at the target at 21.7 MeV, with a 3-mm-diameter beam. The beamline was equipped with four types of spectrometers for experiments in( γ,γ'),( γ,n),( γ,p), and( γ,α). At present, Nuclear Resonance Fluorescence(NRF) spectrometry, Flat-Efficiency neutron Detector(FED) spectrometry, neutron Time-Of-Flight(TOF) spectrometry, and Light-Charged Particle(LCP) spectrometry methods have been developed.

Novel thick-target inverse kinematics method for the astrophysical ^(12)C+^(12)C fusion reaction

The ^(12)C+^(12)C fusion is one of the most important reactions in modern nuclear astrophysics.The trend and magnitude of the reaction rate within the Gamow window strongly influence various astrophysical processes.However,direct measurement of this reaction is extremely difficult,which makes it necessary to develop indirect methods.In this study,the ^(23)Na+p reaction system was used to study the compound nucleus ^(24)Mg.We employed a thick-target inverse kinematics method combined with theγ-charged-particle coincidence technique to measure the proton andα exit channels of ^(24)Mg.Technical details of the ^(23)Na+p thick-target inverse kinematics experiment and analysis are presented herein.

A Model for a Dual Universe

A model for a dual universe is proposed, based on the assumption that simultaneously with our universe an anti-matter counterpart was initiated immediately following the Big Bang. At the heart of the model is a primordial anti-particle that differentiates itself from its counterpart, a previously hypothesized S-particle responsible for the formation of our own universe, through its course of rotation. The angular rotation of the anti-particle, in accordance with space-time rotation, together with the counter rotation of the S-particle, resulted in a time difference in the formation processes of both universes and consequently led to a large distance between the spatial locations occupied by our universe and its dual counterpart in the same space-time continuum. The existence of this anti-matter universe might solve the present mystery of matter anti-matter asymmetry and thus explain why hardly any free anti-matter can be observed in our universe. Moreover, the model implicates the possibility of the presence of a repulsive gravitational force exerted by the clusters of anti-particles in the anti-matter universe upon our universe. The repulsive gravitational force from the clusters of antiparticles in the dual universe as a whole upon our universe is completely different from the electrostatic repulsive force between similarly charged particles. It is also different from that due to possible gravitational or anti-gravitational interaction between individual matter and antimatter or particle and its antiparticle that might violate the CPT invariance, the theory of general relativity or the law of energy conservation. It is rather, a kind of negative gravity that affects our universe as a whole, due to the opposite course of rotation of the dual anti-universe relative to ours. The effect of this opposite rotation of the dual universe can cause anti-gravitational waves that penetrate our universe interacting with the space-time mesh around the galaxies in our universe as a whole, resulting in a negative-like curvature in the shape of the space around them. This negative curvature pushes the galaxies outward, away from each other, leading to the accelerated expansion of our universe. The continuous anti-gravitational waves that permeate and fill our universe might cause a constant background ripples (space fluctuations) in the space of our solar system that can be experimentally observed. The repulsive force exerted by our dual universe could together with the expansion of space-time, influence our universe and might yield more insight on the origin of dark energy. .

The Mysterius Fate of Stars (Past, Present and Future of the Universe)

The research on the collapse of stars, due to Gravity, after the depletion of the fusion fuel, engaged a number of famous guys as Eddington, Chandrasekhar, Schwarzschild and Oppenheimer in the years around 1910-1050. During this period, Einstein was writing his field equation of general relativity (1923), Fermi, in a famous letter to Pauli, proposed the neutrino in beta decay theory (1930), Chadwick found the neutron, that granted him the Nobel price (1935) and Hubble (1929) proved that the Universe was expanding. As a result of that golden age, we remain with a lot of unsolved questions, due to the poor knowledge of the nature of the strong Nuclear Interaction of Gravity that controls the whole Universe. We have made an investigation on the nature of nuclear bond and gravitational attraction on the basis of available data and as a follow-up of Fermi famous research on Neutrino. Using this background, we hope to be able to explain or give some light to the evolution of stars, to the strange objects and phenomena captured or perceived by astronomers in the sky and speculated by theoretical physicists.