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A magnetic bald-patch flare in solar active region 11117

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research in Astronomy and astrophysics 2017年第9期17卷 51-60页

作者： Chao-Wei Jiang Xue-Shang Feng Shi-Tsan Wu Qiang Hu institute of space Science and Applied Technology Harbin Institute of Technology SIGMA Weather Group State Key Laboratory for Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences Center for space Plasma and Aeronomic research The University of Alabama in Huntsville

With SDO observations and a data-constrained magnetohydrodynamics （MHD） model, we identify a confined multi-ribbon flare that occurred on 2010 October 25 in solar active region 11117 as a magnetic bald patch （BP） flare with strong evidence. From the photospheric magnetic field observed by SDO/HMI, we find there are indeed magnetic BPs on the polarity inversion lines （PILs） which match parts of the flare ribbons. From the 3D coronal magnetic field derived from an MHD relaxation model constrained by the vector magnetograms, we find strikingly good agreement of the BP separatrix surface （BPSS） footpoints with the flare ribbons, and the BPSS itself with the hot flaring loop system. Moreover, the triggering of the BP flare can be attributed to a small flux emergence under the lobe of the BPSS, and the relevant change of coronal magnetic field through the flare is reproduced well by the pre-flare and post-flare MHD solutions, which match the corresponding pre- and post-flare AIA observations, respectively. Our work contributes to the study of non-typical flares that constitute the majority of solar flares but which cannot be explained by the standard flare model.

关键词： Sun flares -- Sun corona- magnetic fields - magnetohydrodynamics (MHD) - methods numerical

A 2.05 eV AlGaInP sub-cell used in next generation solar cells

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Journal of Semiconductors 2014年第9期35卷 83-86页

作者：陆宏波李欣益张玮周大勇石梦奇孙利杰陈开建 research Center for Photovoltaics Shanghai Institute of Space Power-Source

An Al0.13GalnP sub-cell used as the top cell in the next generation of high efficiency multi-junction solar cells is fabricated. An efficiency of 10.04% with 1457.3 mV in Voc and 11.9 mA/cm2 in Isc was obtained. QE comparison was carried out to verify the influence of an O-related defect introduced by the high Al-content materials on the cell performance during MOCVD growth. Hetero-structures are employed to confirm the origin of the decreasing short circuit current density compared to a GalnP single junction solar cell. An effective method to improve the performance of broadband solar cells by increasing Isc with a cost of Voc was proposed.

关键词： broadband solar cell heterojunction

Satellite range scheduling with the priority constraint: An improved genetic algorithm using a station ID encoding method

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Chinese Journal of Aeronautics 2015年第3期28卷 789-803页

作者： Li Yuqing Wang Rixin Liu Yu Xu Minqiang Deep space Exploration research Center Harbin Institute of Technology Harbin University of Commerce

Abstract Satellite range scheduling with the priority constraint is one of the most important prob lems in the field of satellite operation. This paper proposes a station coding based genetic algorithm to solve this problem, which adopts a new chromosome encoding method that arranges tasks according to the ground station ID. The new encoding method contributes to reducing the complex ity in conflict checking and resolving, and helps to improve the ability to find optimal resolutions. Three different selection operators are designed to match the new encoding strategy, namely ran dom selection, greedy selection, and roulette selection. To demonstrate the benefits of the improved genetic algorithm, a basic genetic algorithm is designed in which two cross operators are presented, a singlepoint crossover and a multipoint crossover. For the purpose of algorithm test and analysis, a problemgenerating program is designed, which can simulate problems by modeling features encountered in realworld problems. Based on the problem generator, computational results and analysis are made and illustrated for the scheduling of multiple ground stations.

关键词： Genetic algorithm Ground space scheduling Priority Satellite range scheduling space communication

An improved nonlinear control strategy for deep space formation flying spacecraft

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Acta Mechanica Sinica 2009年第6期25卷 847-856页

作者： Peng Li Pingyuan Cui Hutao Cui Deep space Exploration research Center,Harbin institute of Technology, 150080 Harbin, China Deep space Exploration research Center Harbin Institute of Technology 150080 Harbin China

This paper aims to provide further study on the nonlinear modeling and controller design of formation flying spacecraft in deep space missions. First, in the Sun-Earth system, the nonlinear formation dynamics for the circular restricted three-body problem （CRTBP） and elliptic restricted three-body problem （ERTBP） are presented. Then, with the Floquet mode method, an impulsive controller is developed to keep the Chief on the desired Halo orbit. Finally, a nonlinear adaptive control scheme based on Nonzero set- point LQR and neural network is proposed to achieve high precision formation maneuver and keeping. The simulation results indicate that the proposed nonlinear control strategy is reasonable as it considers not only the orbit keeping of the Chief, but also the formation modeling inaccuracy. Moreover, the nonlinear adaptive control scheme is effective to improve the control accuracy of the formation keeping.

关键词： spacecraft formation flying. Libration pointHalo orbit - Nonlinear control

Preface： High Energy astrophysics

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Frontiers of physics 2013年第6期8卷 605-608页

作者： Bing Zhang Peter Mesaros kavli institute for Astronomy and astrophysics and Department of Astronomy Peking University China Department of Physics and Astronomy University of Nevada Las Vegas USA Department of Astronomy and astrophysics Department of Physics and Center for Particle and Gravitational Astrophysics Pennsylvania State University University Park PA 16802 USA

High energy astrophysics is one of the most active branches in the contemporary astrophysics. It studies astrophysical objects that emit X-ray and γ-ray photons, such as accreting super-massive and stellar-size black holes, and various species of neutron stars. With the operations of many space-borne and ground-based observational facilities, high energy astrophysics has enjoyed rapid development in the past decades. It is foreseen that the field will continue to advance rapidly in the coming decade, with possible ground-breaking discoveries of astrophysical sources in the high-energy neutrino and gravitational wave channels. This Special Issue of Frontiers of Physics is dedicated to a systematic survey of the field of high energy astrophysics as it stands in 2013.

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A cceleration of Ionospheric Out-Flowing Ions in the Substorm in Geo-magnetotail

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Chinese Physics Letters 1999年第12期16卷 908-910页

作者： SHI Jian-kui LIU Zhen-Xing T.L.Zhang K.Torkar Center for space Science&Applied research Chinese Academy of SciencesBeijing 100080 space research institute Austrian Academy of SciencesA-8010 GrazAustria

Using dynamics equation, acceleration of out-flowing ion during dipolarization in a substorm in the magneto-tail is simulated. The main results show that: (1) The ion distribution function that is initially exponentially decreasing with increasing speed is turned into a single peak distribution, and with time the peak moves towards higher speed. (2) The peak moves along V⊥ faster than that along V||, and the ion acceleration mainly occurs in the middle of the dipolarization. (3) The higher the initial energy, the faster the peak moves, and the more energy is obtained by the ions. The ion energy theoretically calculated is as high as about 102 keV, this is consistent with the observation.

关键词： storm faster acceleration

Orbital X-ray modulation study of three supergiant HMXBs

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research in Astronomy and astrophysics 2009年第12期9卷 1303-1316页

作者： Chetana Jain Biswajit Paul Anjan Dutta Department of Physics and astrophysics University of Delhi Raman research institute SadashivnagarC.V.Raman Avenue

We present the orbital X-ray modulation study of three high mass X-ray binary systems, IGR J18027-2016, IGR J18483-0311 and IGR J16318-4848, using data obtained with RXTE-ASM, Swift-BAT and INTEGRAL-ISGRI. Using the long term light curves of the eclipsing HMXB IGR J18027-2016, obtained with Swift-BAT in the energy range 15-50keV and INTEGRAL-ISGRI in the energy range 22-40 keV, we have determined three new mid eclipse times. The newly determined mid eclipse times together with the known values were used to derive an accurate value of the orbital period of 4.5693（4） d at MJD 52168 and an upper limit of 3.9（1.2）×10^-7d d-1 on the period derivative. We have also accurately determined an orbital period of 18.5482（88）d for the intermediate system IGR J 18483-0311, which displays an unusual behavior and shares many properties with the known SFXTs and persistent supergiant systems. This is a transient source and the outbursts occur intermittently at intervals of 18.55 d. Similarly, in the third supergiant system, IGR J16318-4848, we have found that the outbursts are separated by intervals of 80 d or its multiples, suggesting a possible orbital period.

关键词： X-ray: neutron stars -- X-ray binaries: individual

Interplanetary Coronal Mass Ejections between 0.3 and 30 AU: Multi-spacecraft Observations and Model Comparison

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Interplanetary Coronal Mass Ejections between 0.3 and 30 AU:...

Fabry-Prot based narrow band imager for solar filament observations

第十一届全国日地空间物理学术讨论会

作者： J.D.Richardson kavli institute for astrophysics and space research Massachusetts institute of Technology 37-655 Cambridge MA 02139 USA

＜正＞Using observations from multiple spacecraft such as Helios, PVO, ACE, Ulysses and Voyager 2 which are distributed throughout the heliosphere, we identify and characterize interplanetary coronal mass ejections （ICMEs） between 0.3 and 30 AU. An abnormally low proton temperature is used as the primary identification signature of ICMEs. The occurrence rate of ICMEs approximately follows the solar activity cycle. Statistically, the average radial width of ICMEs increases with distance up to about 15 AU, with a radial expansion speed of the order of the Alfven speed. The expansion features of the average temperature, density, and magnetic field magnitude of ICMEs are also studied. We employ a one-dimensional MHD numerical code to model the propagation of ICMEs to try to understand the observations. The model results reproduce the basic expansion characteristics of ICMEs.

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research in Astronomy and astrophysics 2016年第1期16卷 79-88页

作者： Sajal Kumar Dhara Belur Ravindra Ravinder Kumar Banyal Indian institute of astrophysics Bangalore-560034 India

We have recently developed a narrow band imager（NBI） using an air gap based Fabry-P′erot（FP） interferometer at the Indian institute of astrophysics, Bangalore. Narrow band imaging is achieved by using an FP interferometer working in combination with an order sorting pre-filter. The NBI can be tuned to a different wavelength position on the line profile by changing the plate separation of the FP. The interferometer has a 50 mm clear aperture with a bandpass of ～247.8 m ？A and a free spectral range of～5.3 ？A at λ = 656.3 nm. The developed NBI is used to observe the solar filament in the Hα *** instrument is being used to image the Sun at chromospheric height and it is also able to scan the Hα spectral line profile at different wavelength positions. We have also made Doppler velocity maps at chromospheric height by taking the blue and red wing images at ±176 m ？A wavelength positions separately away from the line center of the spectral line. In this paper, we present a description of the NBI including lab test results of individual components and some initial observations carried out with this instrument.

关键词： instrumentation: interferometers -- instrumentation: spectrographs -- methods: observational-- Sun: chromosphere -- Sun: filaments/prominences