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Research in Astronomy and Astrophysics 2009年第10期9卷 1155-1164页

作者： you-ping li wei-qun gan yang su Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China

Among the RHESSI flare samples, we concentrated on a kind of flare that presents two successive peaks （that is, it presents both an impulsive phase and a gradual phase） in 12 - 25 keV light curves. Taking the C1.4 flare on 2002 August 12 as an example, we studied the light curves, spectra, and images in detail. Making full use of the capabilities of RHESSI, we showed some evidence to support the expected causal relationship between these two peaks; the first peak is mainly nonthermal, while the second peak is mainly thermal; the energy carried by nonthermal electrons during the first peak seems to be comparable to the thermal energy of the second peak. The morphologies of X-ray images and their evolutions provide additional evidence for this causality. We conclude that two such peaks in the 12 - 25 keV light curve are good evidence for the chromospheric evaporation. However, the maximum time of the second peak is later than the end time of the first peak, suggesting that for some events, a modification of the traditional Neupert effect could be necessary by inclusion of a time delay, which might be partly related to the filling of the loop by evaporated material.

关键词： sun flares -- sun X-rays, gamma-rays

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

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Nuclear Science and Techniques 2024年第8期35卷 142-152页

作者： Yin‑Ji Chen Hao Zhang li‑Yong Zhang Jian‑Jun He Richard James deBoer Michael Wiescher Alexander Heger David Kahl Jun su Daniel Odell Xin‑Yue li Jian‑Guo Wang Long Zhang Fu‑Qiang Cao Zhi‑Cheng Zhang Xin‑Zhi Jiang Luo‑Huan Wang Zi‑Ming li Lu‑yang Song liang‑Ting sun Qi Wu Jia‑Qing li Bao‑qun Cui li‑Hua Chen Rui‑gang Ma Er‑Tao li gang lian Yao‑De Sheng Zhi‑Hong li Bing Guo wei‑ping liu Key Laboratory of Beam Technology of the Ministry of Education College of Nuclear Science and TechnologyBeijing Normal UniversityBeijing 100875China Department of Physics and Astronomy The Joint Institute for Nuclear AstrophysicsUniversity of Notre DameNotre DameIN 46556USA School of Physics and Astronomy Monash UniversityClaytonVIC 3800Australia Facility for Rare Isotope Beams Michigan State UniversityEast LansingMI 48824USA Institute of Nuclear and Particle Physics and Department of Physics and Astronomy Ohio UniversityAthensOH 45701USA Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China China Institute of Atomic Energy Beijing 102413China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China College of Science Southern University of Science and TechnologyShenzhen 518055China Institute of Radiation Technology Beijing Academy of Science and TechnologyBeijing 100875China Key Laboratory of Nuclear Physics and Ion‑Beam Application(MOE) Institute of Modern PhysicsFudan UniversityShanghai 200433China School of Mathematics and Physics Handan UniversityHandan 056005China

Calcium production and the stellar evolution of first-generation stars remain fascinating mysteries in *** 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 ***,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 *** performed a direct measurement of this break-out reaction at the China Jinping underground *** measurement was performed down to the low-energy limit of E_(c.m.)=186 keV in the center-of-mass *** key resonance was observed at 225.2 keV for the first *** 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 *** 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 *** break-out resulted in the production of the calcium observed in the oldest stars,enhancing our understanding of the evolution of the first stars.

关键词： Nuclear astrophysics First stars Abundance of calcium Reaction cross section Reaction rate China Jinping underground laboratory(CJPL) JUNA

On the power-law distributions of X-ray fluxes from solar flares observed with GOES

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Research in Astronomy and Astrophysics 2016年第10期16卷 99-106页

作者： you-ping li li Feng ping Zhang Si-Ming liu wei-qun gan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of Sciences

The power-law frequency distributions of the peak flux of solar flare X-ray emission have been studied extensively and attributed to a system having self-organized criticality （SOC）. In this paper, we first show that, so long as the shape of the normalized light curve is not correlated with the peak flux, the flux histogram of solar flares also follows a power-law distribution with the same spectral index as the power- law frequency distribution of the peak flux, which may partially explain why power-law distributions are ubiquitous in the Universe. We then show that the spectral indexes of the histograms of soft X-ray fluxes observed by GOES satellites in two different energy channels are different： the higher energy channel has a harder distribution than the lower energy channel, which challenges the universal power-law distribution predicted by SOC models and implies a very soft distribution of thermal energy content of plasmas probed by the GOES satellites. The temperature （T） distribution, on the other hand, approaches a power-law dis- tribution with an index of 2 for high values of T. Hence the application of SOC models to the statistical properties of solar flares needs to be revisited.

关键词： sun: flares -- sun: X-rays Gamma rays -- methods: statistical

Study of a solar flare on 2005 August 22 observed in hard X-rays and microwaves

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Research in Astronomy and Astrophysics 2015年第1期15卷 64-76页

作者： Zhong-Yin liu you-ping li wei-qun gan Kazi A.Firoz Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Space Research Group Alcala University28871 Alcala de Henares Spain

We investigate the 2005 August 22 flare event（00：54 UT） exploiting hard X-ray（HXR） observations from the Reuven Ramaty High Energy Solar Spectroscopic Imager（RHESSI） and microwave（MW） observations from the Nobeyama Solar Radio Observatory. The HXR time profile exposes well-damped quasi-periodic pulsations with four sequential peaks, and the MW time profile follows the corresponding *** on this feature, we derive the time relationship of HXRs and MWs with multifrequency data from the Nobeyama Radio Polarimeter, and the spatially resolvable data from RHESSI and the Nobeyama Radioheliograph. We find that both frequency dependent delays in MWs and energy dependent delays in HXRs are ***, MW emissions from the south source are delayed with respect to those from the north source at both 17 GHz and 34 GHz, but no significant delays are found in HXR emissions from the different sources at the same energies. To better understand all these long time delays, we derive the electron fluxes of different energies by fitting the observed HXR spectra with a single power-law thick-target model, and speculate that these delays might be related to an extended acceleration process. We further compare the time profile of a MW spectral index derived from 17 and 34 GHz fluxes with the flux densities, and find that the spectral index shows a strong anticorrelation with the HXR fluxes.

关键词： sun: flares sun: radio radiation sun: X-rays,gamma rays

The breakdown of the power-law frequency distributions for the hard X-ray peak count rates of solar flares

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Research in Astronomy and Astrophysics 2013年第12期13卷 1482-1492页

作者： you-ping li wei-qun gan li Feng Si-Ming liu A.Struminsky Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of Sciences Space Research Institute(IKI) Russian Academy of Science

The frequency distribution for several characteristics of a solar flare obeys a power law only above a certain threshold, below which there is an apparent loss of small scale events presumably caused by limited instrumental sensitivity and th：e corresponding event selection bias. It is also possible that this deviation in the power law can have a physical origin in the source. We propose two fitting models incorpo- rating a power law distribution with a low count rate cutoff plus a noise component for the frequency distribution of the hard X-ray peak count rate of all solar flare sam- ples obtained with HXRBS/SMM and BATSE/CGRO observations. Our new fitting method produces the same power-law index as previously developed methods, a low cutoff of the power-law function and its corresponding noise level, which is consistent with measurements of the actual noise level of the hard X-ray count rate. We found that the fitted low cutoff appears to be related to the noise level, i.e., flares are only recognized when their peak count rate is 3or greater than noise. Therefore, the fitted low cutoff, which is smaller than the aforementioned threshold, might be attributed to selection bias, and probably not to the actual count rate cutoff in flares at smaller scales. Whether or not the actual low cutoff physically exists needs to be checked by future observations with increased sensitivities.

关键词： sun: flares -- sun: X-rays gamma-rays -- methods: statistical

The Science Operations and Data Center (SODC) of the ASO-S mission

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Research in Astronomy and Astrophysics 2019年第11期19卷 103-109页

作者： Yu Huang Hui li wei-qun gan you-ping li Jiang-Tao su Yuan-Yong Deng li Feng yang su wei Chen Shi-Jun Lei Ying li Yun-Yi Ge Ying-Na su Si-Ming liu Jing-Jing Zang Zun-Lei Xu Xian-Yong Bai Jing-wei li Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210034China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

A ground data analysis center is very important to the success of a *** introduce the Science Operations and Data Center(SODC)for the ASO-S mission,which consists of a scientific operation subcenter,a data management subcenter,a data analysis subcenter and a user service *** mission planning process,instrument observation modes and the data volume are *** describe the data flow and processing procedures from spacecraft telemetry to high-level science data,and the long-term archival as *** data policy and distributions are also briefly introduced.

关键词： space vehicles:instruments methods:data analysis techniques:image processing

Simulations and software development for the Hard X-ray Imager onboard ASO-S

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Research in Astronomy and Astrophysics 2019年第11期19卷 93-102页

作者： yang su wei liu you-ping li Zhe Zhang Gordon JHurford wei Chen Yu Huang Zhen-Tong li Xian-Kai Jiang Hao-Xiang Wang Fan-Xiao-Yu Xia Chang-Xue Chen Wen-Hui Yu Fu Yu Jian Wu wei-qun gan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210034China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China University of Applied Sciences and Arts Northwestern Switzerland Bahnhofstrasse 65210WindischSwitzerland Space Science Laboratory University of California7 Gauss Way94720 BerkeleyUSA School of Space Science and Physics Shandong UniversityWeihai 264209China

China’s first solar mission,the Advanced Space-based Solar Observatory(ASO-S),is now changing from Phase B to Phase *** main scientific objectives are summarized as’1M2B’,namely magnetic field and two types of bursts(solar flares and coronal mass ejections).Among the three scientific payloads,Hard X-ray Imager(HXI)observes images and spectra of X-ray bursts in solar *** this paper,we briefly report on the progresses made by the HXI science team(data and software team)during the design phase(till May 2019).These include simulations of HXI imaging,optimization of HXI grids,development of imaging algorithms,estimation of orbital background,as well as in-orbit calibration *** efforts provided guidance for the engineering,improved HXI’s imaging capability and reduced the cost of the instrument.

关键词： techniques X-ray imaging-techniques simulation sun X-rays-sun flares

On the Positronium Continuum and 0.511 MeV line in Solar Flares

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Chinese Journal of Astronomy and Astrophysics 2004年第4期4卷 357-364页

作者： wei-qungan JinChang you-pingli yangsu L.I.Miroshnichenko PurpleMountainObservatory ChineseAcademyofSciencesNanjing210008 IZMIRAN TroitskMoscowRegion142190Russia

We have studied the influence of the density of the annihilation region on the positronium continuum. A relation between the ratio 3γ/2γ and the density is explicitly given, with which one can derive directly from the observed 3γ/2γ the density where the annihilation occurs. A unique solution may be found from the observed width of the 0.511 MeV line. We applied the method to three flares observed by GRS/SMM. It is shown that due to the measuring uncertainties in the 0.511 MeV line width, we cannot distinguish a chromospheric source from a coronal source, though both accurately localized. To improve the measuring accuracy of the 0.511 MeV line and the ratio 3γ/2γ will be an important step for a better understanding of the annihilation process in solar flares.

关键词： sun: flares sun: X-rays gamma-rays

On the Evolution of the Lower Energy Cutoff of Nonthermal Electrons in Solar Flares

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Chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 103-105页

作者： wei－qungan you－pingli 等 PurpleMountainObservatory ChineseAcademyofSciencesNanjing210008 NationalAstronomicalObservatories ChineseAcademyofSciencesBeijing100012

Using the method recently developed by Can et al. (2001a, 2002), We investigate the time variation of the lower energy cutoff (Ec) of nonthermal electrons for three BATSE/CGRO hard X-ray events. The result shows that Ec changes with time, from smaller before the peak flux, to larger at the peak, and then back to smaller after the peak. such a variation of Ec, being a preliminary conclusion for the first time, should be checked in the future by using data with a higher energy resolution.

关键词： sun: hard X-rays─sun: gamma-rays─sun: flares─sun: particles

Advanced Space-based Solar Observatory(ASO-S):an overview

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Research in Astronomy and Astrophysics 2019年第11期19卷 3-10页

作者： wei-qun gan Cheng Zhu Yuan-Yong Deng Hui li yang su Hai-Ying Zhang Bo Chen Zhe Zhang Jian Wu Lei Deng Yu Huang Jian-Feng yang Ji-Jun Cui Jin Chang Chi Wang Ji Wu Zeng-Shan Yin Wen Chen Cheng Fang Yi-Hua Yan Jun lin wei-Ming Xiong Bin Chen Hai-Chao Bao Cai-Xia Cao Yan-ping Bai Tao Wang Bing-Long Chen Xin-Yu li Ye Zhang li Feng Jiang-Tao su Ying li wei Chen you-ping li Ying-Na su Hai-Yan Wu Mei Gu Lei Huang Xue-Jun Tang Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210034China Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201203China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China Nanjing Institute of Astronomical Optics&Technology National Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China Changchun Institute of Optics Fine Mechanics and PhysicsChangchun 130033China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of SciencesXi’an 710119China National Space Science Center Chinese Academy of SciencesBeijing 100190China School of Astronomy and Space Science Nanjing UniversityNanjing 210023China Yunnan Observatories Chinese Academy of SciencesKunming 650011China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 101408China Beijing Special Engineering and Design Institute Beijing 100028China Beijing Institute of Tracking and Telecommunications Technology Beijing 100094China Shanghai Academy of Spaceflight Technology Shanghai 201109China

The Advanced Space-based Solar Observatory(ASO-S)is a mission proposed for the 25 th solar maximum by the Chinese solar *** scientific objectives are to study the relationships between the solar magnetic field,solar flares and coronal mass ejections(CMEs).Three payloads are deployed:the Full-disk vector Magneto Graph(FMG),the Lyman-αSolar Telescope(LST)and the Hard X-ray Imager(HXI).ASO-S will perform the first simultaneous observations of the photospheric vector magnetic field,non-thermal imaging of solar flares,and the initiation and early propagation of CMEs on a single ***-S is scheduled to be launched into a 720 km sun-synchronous orbit in *** paper presents an overview of the mission till the end of Phase-B and the beginning of Phase-C.

关键词： space vehicles instruments-sun magnetic fields-sun flares-sun CMEs-sun UV radiation-sun X-ray,gamma-rays