【摘要】：本文在多成分單流體MHD模擬基礎(chǔ)上,計(jì)算了火星空間大尺度電流體系,并對(duì)磁異常對(duì)火星空間電流的影響進(jìn)行了分析。其結(jié)果表明,火星空間存在著弓激波電流、磁堆積區(qū)邊界電流、電離層電流和磁尾中心電流片。磁異常對(duì)四種電流均有不同程度的影響。 火星空間大尺度電流分布的特點(diǎn)有,弓激波電流在弓激波曲面上均由北流向南,自成體系,電流方向垂直于行星際磁場(chǎng)方向,電流強(qiáng)度在弓激波頂區(qū)域較大。磁堆積區(qū)邊界電流均由北向南流動(dòng)形成兩支電流,在向陽面與電離層電流構(gòu)成回路,而在背陽面和磁尾中心電流片耦合形成完整的回路。磁尾中心電流片在近火星1.3RM內(nèi)受火星電離層影響較大,會(huì)分離為兩支或更多電流片耦合在一起。電離層電流強(qiáng)度是所有電流體系中最大的,平均電流強(qiáng)度都在100nA/m2以上,且向陽面電流強(qiáng)度均比背陽面大。 磁異常對(duì)四種電流有著不同的影響。磁異常的存在使弓激波電流曲率比沒有磁異常時(shí)要大些,激波面的平均位置離火星也會(huì)更遠(yuǎn)一點(diǎn)。磁異常使向陽面磁堆積區(qū)邊界電流強(qiáng)度增大了很多,電流流線形態(tài)也變得不太規(guī)律;背陽面磁堆積區(qū)邊界電流的南北流入、流出源連線的位置同時(shí)發(fā)生了偏移,磁堆積區(qū)兩瓣的電流半徑也變得更大些。不過磁異常的影響使火星南北兩極區(qū)的磁堆積區(qū)電流分布的高度變低了,形態(tài)也更規(guī)律些。磁異常使磁尾中心電流片的影響有限,使其與子午面存在著一定的夾角,在背陽面離火星中心1.8RM范圍之內(nèi),近火表面磁尾中心電流片會(huì)有多條電流片耦合在一起。磁異常對(duì)電離層電流的影響較大,使火星電離層局部電流強(qiáng)度增強(qiáng)很大,尤其在南半球電流強(qiáng)度可達(dá)上萬nA/m2,但整體上并沒有改變向陽面和背陽面的電流強(qiáng)度分布差異的特點(diǎn)。磁異常也并沒有改變電離層的電流整體由南極附近流向北極的趨勢(shì),不過使流線分布變得很復(fù)雜,部分區(qū)域變得非常雜亂,尤其在南半球電流強(qiáng)度較強(qiáng)處出現(xiàn)了打圈、褶皺等現(xiàn)象。
[Abstract]:Based on the multi-component single-fluid MHD simulation, the large scale current system of Mars space is calculated, and the influence of magnetic anomaly on the space current of Mars is analyzed. The results show that there are bow shock current, boundary current in magnetic accumulation region, ionospheric current and central current sheet in the space of Mars. Magnetic anomalies have different effects on the four kinds of currents. The characteristics of large scale current distribution in Mars space are as follows: the current of bow shock wave is from north to south on the surface of the bow shock wave, and the current direction is perpendicular to the interplanetary magnetic field, and the current intensity is larger in the area of the top of the bow shock wave. The boundary currents flow from north to south to form two currents in the magnetic stacking area, which form a circuit with the ionospheric current on the positive surface, and a complete circuit is formed on the back positive surface and the central current sheet of the magnetotail. The magnetotail central current sheet is strongly influenced by the Mars ionosphere in the near Mars 1.3RM and will be separated into two or more current sheets coupled together. The ionospheric current intensity is the largest in all current systems, the average current intensity is above 100nA/m2, and the positive current intensity is higher than that of the back positive current system. Magnetic anomalies have different effects on the four kinds of currents. Due to the existence of magnetic anomalies, the curvature of the bow shock current is larger than that without the magnetic anomaly, and the average position of the shock surface is farther away from Mars. Because of the magnetic anomaly, the boundary current intensity increases a lot and the current flow pattern becomes irregular. The position of the line of the outflow source is shifted simultaneously, and the current radius of the two lobes in the magnetic packing area becomes larger as well as the north and south inflow of the boundary current in the magnetic stacking area on the back positive surface. However, the effect of magnetic anomalies has reduced the height of the current distribution in the magnetic accumulation region in the north and south poles of Mars, and the pattern is more regular. The effect of magnetic anomaly on the central current sheet is limited and there is a certain angle between it and the meridional plane. Within the range of the back positive surface from the central 1.8RM of Mars, there will be a number of current sheets coupled together in the near surface of the magnetotail current sheet. The magnetic anomaly has a great influence on the ionospheric current, which increases the local current intensity of the Mars ionosphere, especially in the Southern Hemisphere, where the current intensity can reach tens of thousands of nA/m2,. But on the whole, it does not change the characteristics of the distribution of the current intensity toward the positive and the back. The magnetic anomalies have not changed the overall trend of the ionospheric current flowing from the South Pole to the North Pole, but the streamline distribution has become very complicated, and some areas have become very messy, especially in the southern hemisphere where the current intensity is relatively strong. Fold, etc.
【學(xué)位授予單位】：中國(guó)科學(xué)院研究生院（空間科學(xué)與應(yīng)用研究中心）
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：P185.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 張藝騰;李磊;;火星空間磁場(chǎng)結(jié)構(gòu)特征[J];空間科學(xué)學(xué)報(bào);2009年03期

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本文編號(hào)：2352558