闪电回击过程物理机制研究

阐述了云地闪发生的物理过程,并根据国外一些类比实验对云地闪发生的物理机制进行了分析,主要就先导过程中电晕套的形成机制和回击过程中电晕套中空间电荷的中和机理做出解释.     

Exploring coronal structures with SOHO

We applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.     

Numerical boundary conditions for solar magnetohydrodynamic flows using the method of characteristics

We discuss the self-consistent time-dependent numerical boundary conditions on the basis of theory of characteristics for magnetohydrodynamics (MHD) simulations of solar plasma flows. The importance of using self-consistent boundary conditions is demonstrated by using an example of modeling coronal dynamic structures. This example demonstrates that the self-consistent boundary conditions assure the correctness of the numerical solutions. Otherwise, erroneous numerical solutions will appear.     

类环状CMEs形成的数值模拟

对于不同磁场强度冕旒位形中，热驱动日冕瞬变的数值模拟表明，β（＝2μ₀P／B²）值的大小对瞬变的形态有重要的控制作用，只有β较小（如太阳表面赤道处β₀等于0.25）时才可重现典型环状CMEs观测形态：足部出现在开场与闭场的交界面上，在纬向基本不动；CMEs顶部物质变化在传播过程中沿电流片两侧移动，使顶部物质密度变化比两侧小．     

The Large Angle Spectroscopic Coronagraph (LASCO)

The Large Angle Spectroscopic Coronagraph (LASCO) is a three coronagraph package which has been jointly developed for the Solar and Heliospheric Observatory (SOHO) mission by the Naval Research Laboratory (USA), the Laboratoire d'Astronomie Spatiale (France), the Max-Planck-Institut für Aeronomie (Germany), and the University of Birmingham (UK). LASCO comprises three coronagraphs, C1, C2, and C3, that together image the solar corona from 1.1 to 30 R (C1: 1.1 – 3 R, C2: 1.5 – 6 R, and C3: 3.7 – 30 R). The C1 coronagraph is a newly developed mirror version of the classic internally-occulted Lyot coronagraph, while the C2 and C3 coronagraphs are externally occulted instruments. High-resolution imaging spectroscopy of the corona from 1.1 to 3 R can be performed with the Fabry-Perot interferometer in C1. High-volume memories and a high-speed microprocessor enable extensive on-board image processing. Image compression by a factor of about 10 will result in the transmission of 10 full images per hour.     

POLAR investigation of the Sun—POLARIS

The POLAR Investigation of the Sun (POLARIS) mission uses a combination of a gravity assist and solar sail propulsion to place a spacecraft in a 0.48 AU circular orbit around the Sun with an inclination of 75° with respect to solar equator. This challenging orbit is made possible by the challenging development of solar sail propulsion. This first extended view of the high-latitude regions of the Sun will enable crucial observations not possible from the ecliptic viewpoint or from Solar Orbiter. While Solar Orbiter would give the first glimpse of the high latitude magnetic field and flows to probe the solar dynamo, it does not have sufficient viewing of the polar regions to achieve POLARIS’s primary objective: determining the relation between the magnetism and dynamics of the Sun’s polar regions and the solar cycle.

日冕物质抛射的数值研究——初态日冕和驱动机制的影响

初态日冕和驱动机制在日冕物质抛射的形成和演化过程中所起的作用是一个引起争论的问题.本文从MHD方程组出发,在不同的初态日冕中,数值模拟了日冕底部新磁通量喷发和热压力扰动两种驱动机制的日冕响应.结果表明,初态日冕和驱动机制对日冕物质抛射的形成及演化都有重要影响.     

雷暴下地面自然尖端电晕放电离子时空演化的数值模拟

为了对雷暴云下近地面的电特性进行分析，本文建立了模拟自然尖端所产生的电晕离子演化的一维数值模式。以地面电场为基础，考虑到地面电晕离子的演化，成功地计算了从地面至８００ｍ的空中电场及电荷、电流的时空演变，发现地面电晕离子可解释除雷暴云电荷影响外的空中电场和地面电场的差异，空间电场比地面电场更能反应雷暴电荷所产生的电场。空间电荷层可延伸到８００ｍ的高度上，且电荷密度可高达０．２５ｎＣ／ｍ^３，６００ｍ高度上的传导电流密度可达０．１ｎＡ／ｍ^２。     

汇聚造山带变质矿物冠状反应边及生长环带

哀牢山、澜沧江、高黎贡山、念青唐古拉山等汇聚造山带变质岩中,发现一些标型或特征变质矿物间形成冠状反应边或生长环带。它们是变质过程的真实记录,反映了变形变质环境条件的不断变化,完整或直观地表现了不同地体或构造带PTt轨迹特征。可帮助恢复汇聚造山带中不同地体构造属性,为研究造山带PTtD轨迹和PTDX轨迹,提供准确资料。可从另一侧面了解汇聚造山带的演化史。