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中层顶波非线性相互作用的甚高频雷达观测研究

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电波科学学报 2000年第1期15卷 84-89页

作者：熊建刚易帆 J.Klostermeyer r.rüster 中国科学院武汉物理与数学研究所武汉大学无线电科学技术系武汉430072 max-planck- institutefür aeronomic max-planck-institutefür aeronomic

利用 SOUSY VHF雷达 1 987年 6月 2 2日至 6月 2 9日在挪威 Andoya的观测数据研究了中层顶附近大气风场中行星波、潮汐和惯性重力波的非线性相互作用。首先利用 Lomb- Scargle周期图方法计算了大气纬向风场的功率谱 ,除了行星波和潮汐... 详细信息

利用 SOUSY VHF雷达 1 987年 6月 2 2日至 6月 2 9日在挪威 Andoya的观测数据研究了中层顶附近大气风场中行星波、潮汐和惯性重力波的非线性相互作用。首先利用 Lomb- Scargle周期图方法计算了大气纬向风场的功率谱 ,除了行星波和潮汐外 ,在行星波、潮汐的频率和与频率差处有明显的谱峰 ,双谱分析表明这些谱峰是行星波和潮汐相互作用形成的。在 86.4km处 35h行星波、半日潮与 8.9h惯性重力波有较强的非线性耦合 ,半日潮与行星波间有明显的能量传输。半日潮振幅变化的周期为 78h,远大于行星波的周期。 85.2 km处经向风场半日潮振幅的变化周期同样大于与之相互作用的 33h行星波的周期。

关键词：行星波潮汐中层顶波甚高频雷达惯性重力波

Comparative analyses of current three-dimensional numerical solar wind models

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Science China Earth Sciences 2015年第6期58卷 839-858页

作者： Shi Tsan WU Murray DrYEr Center for Space Plasma and aeronomic research the University of Alabama in Huntsville Space Weather Predictions Center National Weather Service National Oceanic and Atmospheric Administration

We present a comparative study of the most advanced three-dimensional time-dependent numerical simulation models of solar wind. These models can be classified into two categories:(I) theoretical, empirical and numerically based models and(II) self-consistent multi-dimensional numerical magnetohydrodynamic(MHD) models. The models of Category I are used to separately describe the solar wind solution in two plasma flows regions: transonic/trans-Alfvénic and supersonic/super-Alfvénic, respectively. Models of Category II construct a complete, single, numerical solar wind solution through subsonic/sub-Alfvénic region into supersonic/super-Alfvénic region. The Wang-Sheeley-Arge(WSA)/ENLIL in CISM is the most successful space weather model that belongs to Category I, and the Block-Adaptive-Tree-Solarwind-roe-Upwind-Scheme(BATS-r-US) code in SWMF(Space Weather Modeling Framework) and the solar-interplanetary conservative element solution element MHD(SIP-CESE MHD) model in SWIM(Space Weather Integrated Model) are the most commonly-used models that belong to Category II. We review the structures of their frameworks, the main results for solar wind background studies that are essential for solar transient event studies, and discuss the common features and differences between these two categories of solar wind models. Finally, we conclude that the transition of these two categories of models to operational use depends on the availability of computational resources at reasonable cost and point out that the models' prediction capabilities may be improved by employing finer computational grids, incorporating more observational data and by adding more physical constraints to the models.

关键词：数值模拟模型三维数值太阳风空间天气建模框架时间依赖性 MHD 基于模型

A Proposed Gravitodynamic Theory

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Journal of Systems Engineering and Electronics 1995年第4期6卷 265-272页

作者： Tsao Chang (Denter for Space Plasma and aeronomic research, University of Alabama in Huntsville Huntsville,AL 35899, USA) Center for Space Plasma and aeronomic research University of Alabama in Huntsville Huntsville AL 35899 USA

This paper proposes a gravitodynamic theory because there are similarities between gravitational theory and electrodynamics. Based on Einstein's principle of equivalence, two coordinate conditions are proposed into the four-dimensional line element and transformations. As a consequence, the equation of motion for gravitational force or inertial force bas a form similar to the equation of Lorentz force on a charge in electrodynamics. The inertial forces in a uniformly rotating system are calculated, which show that the Coriolis force is produced by a magnetic-type gravitational field. We have also calculated the Sagnac effect due to the rotation. These experimental facts strongly support our proposed coordinate conditions. In addition, the gravitodynamic field equations are briefly discussed. Since only four gravitational potentials (3+1 split) enter the metric tensor, the gravitodynamic field equations in'3+1 split' form would be analogous to maxwell's equations.

关键词： Coordinate conditions Gravitodynamic field equations.

Solar Impulsive Hard X-ray Emission and Two-Stage Electron Acceleration

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Chinese Journal of Astronomy and Astrophysics 2006年第6期6卷 733-740页

作者： Tian-Xi Zhang Arjun Tan Shi Tsan Wu Physics Deparanent Alabama A ＆ M University Normal AL 35762 USA Center for Space Plasma and aeronomic research The University of Alabama in Huntsville AL 35899 USA

Heating and acceleration of electrons in solar impulsive hard X-ray （HXr） flares are studied according to the two-stage acceleration model developed by Zhang for solar ^3Herich events. It is shown that electrostatic H-cyclotron waves can be excited at a parallel phase velocity less than about the electron thermal velocity and thus can significantly heat the electrons （up to 40 MK） through landau resonance. The preheated electrons with velocities above a threshold are further accelerated to high energies in the flare-acceleration process. The flareproduced electron spectrum is obtained and shown to be thermal at low energies and power law at high energies. In the non-thermal energy range, the spectrum can be double power law if the spectral power index is energy dependent or related. The electron energy spectrum obtained by this study agrees quantitatively with the result derived from the reuven ramaty High Energy Solar Spectroscopic Imager （rHESSI） HXr observations in the flare of 2002 July 23. The total flux and energy flux of electrons accelerated in the solar flare also agree with the measurements.

关键词： acceleration of particles - instabilities - plasmas - Sun flares - Sun particle emission - Sun X-ray

Challenges of modeling solar disturbances' arrival times at the Earth

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Science China(Technological Sciences) 2008年第10期51卷 1580-1588页

作者： C. D. FrY Chin-Chun WU Murray DrYEr Center for Space Plasma and aeronomic research The University of Alabama in Huntsville Huntsville AL 35899 USA Exploration Physics International Inc. Huntsville AL 35806 USA Center for Space Plasma and aeronomic research The University of Alabama in Huntsville Huntsville AL 35899 USA Space Weather Laboratory NASA/Goddard Space Flight Center Greenbelt MD 20771 USA Center for Space Plasma and aeronomic research The University of Alabama in Huntsville Huntsville AL 35899 USA Exploration Physics International Inc. Huntsville AL 35806 USA Space Weather Prediction Center National Oceanic and Atmospheric Administration (NOAA) Boulder Colorado USA

In recent years remarkable advances have been made in the development of phys-ics based models of various parts of the solar-terrestrial system (see JASTP special issues, October, November 2004; February 2007). In this paper, we focus our dis-cussions in a specific region of the Sun to the Earth’s environment (i.e. 1 AU). It is well-known that geomagnetic storms are caused by solar eruptions. The conse-quences of these storms include particle acceleration, solar wind impact on the Earth’s magnetosphere and ionosphere, UV-EUV radiation effects on the lower at-mosphere, etc. One of the main challenges is to predict the arrival time at 1 AU of the solar disturbance. The prospects look good for an accurate, real-time forecast scheme built on the acquisition of solar, heliosphere and the near-Earth data and large-scale models. However, the accuracy of these models still needs improve-ment. We will discuss the present status of the models and challenges to improve the simulation models.

关键词： space weather――magnetohydrodynamic (MHD) Modeling MHD Sun-Earth connection MHD Sun-Corona

Magnetoacoustic Waves in the Solar Stratified Atmosphere

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Chinese Physics Letters 2001年第12期18卷 1624-1627页

作者：郑惠南王水吴式灿李波 Department of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026 Center for Space Plasma and aeronomic research and Department of Mechanical Engineering University of Alabama in HuntsvilleHuntsvilleAL 35899USA

The propagation of magnetoacoustic waves in the solar atmosphere consisting of the photosphere, chromosphere and corona has been studied numerically by time-dependent multi-dimensional magnetohydrodynamic (MHD) simulation. Pressure disturbances are introduced at the bottom of the chromosphere and at the bottom of the corona, respectively. The computational results show that incurred fast and slow MHD waves propagate away from the source of the disturbances. The fast MHD wave propagates as an expansive wave in the radial direction, while the slow one steepens and it may evolve into a slow shock. We suggest that the extreme ultraviolet imaging telescope wave observed by the SOHO and Moreton wave are a fast MHD wave propagating in the corona and in the chromosphere, respectively.

关键词： Solar Atmosphere steep

An ACE/CrIS-observation-based Galactic Cosmic rays heavy nuclei spectra model Ⅱ

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Science China(Physics,Mechanics & Astronomy) 2020年第1期63卷 100-111页

作者： Shuai Fu LingLing Zhao Gary PZank Miao Wang Yong Jiang Institute of Space Weather Nanjing University of Information Science and TechnologyNanjing 210044China Center for Space Plasma and aeronomic research(CSPAr) University of Alabama in HuntsvilleHuntsville AL 35805USA Department of Space Science University of Alabama in HuntsvilleHuntsville AL 35899USA

An observation-based Galactic Cosmic ray(GCr)spectral model for heavy nuclei is *** and Qin[*** Phys.118,1837(2013)]proposed an empirical elemental GCr spectra model for nuclear charge 5≤z≤28 over the energy range^30 to 500 Me V/nuc,which is proved to be successful in predicting yearly averaged GCr heavy nuclei *** on the latest highly statistically precise measurements from ACE/CrIS,a further elemental GCr model with monthly averaged spectra is *** model can reproduce the past and predict the future GCr intensity monthly by correlating model parameters with the continuous sunspot number(SSN)*** effects of solar activity on GCr modulation are considered separately for odd and even solar *** with other comprehensive GCr models,our modeling results are satisfyingly consistent with the GCr spectral measurements from ACE/SIS and IMP-8,and have comparable prediction accuracy as the Badhwar&O’Neill 2014 model.A detailed error analysis is also ***,the GCr carbon and iron nuclei fluxes for the subsequent two solar cycles(SC 25 and 26)are predicted and they show a potential trend in reduced flux amplitude,which is suspected to be relevant to possible weak solar cycles.

关键词： Galactic Cosmic rays spectral model solar modulation heavy nuclei

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

Exact traveling wave solutions of some nonlinear physical *** fifth order KdV type equations

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Communications in Nonlinear Science and Numerical Simulation 2000年第3期5卷 118-124页

作者： Jianlan HU X. FENG and Zhi LI(Department of Applied Mathematics, Beijing Polytechnic University, Beijing 100022, ChinaCenter for Space Plasma and aeronomic research / Department of Mechanical and Aerospace Engineering, University of Alabama in Huntsville Department of Applied Mathematics Beijing Polytechnic University Beijing 100022 China Center for Space Plasma and aeronomic research / Department of Mechanical and Aerospace Engineering University of Alabama in Huntsville Huntsville AL 35899 USA Department of Mechanics & Engineering Science Peking University Beijing 100871 China

New exact traveling wave solutions are derived for the fifth order KdV type equations by using a delicate way of rank analysis two-step ansatz method. Solitary shallowwater waves described by the above equation are di... 详细信息

关键词： the fifth order KdV type equations exact traveling wave solution solitary waves rank analysis method