火星磁层中O^＋离子分布的理论研究

对火星磁层中背阳面区来自电离层的Ｏ＋离子沿磁力线的密度和通量密度分布进行了理论研究．设火星的磁场由内禀磁场和感应磁场相叠加而成，结合不同的内禀磁矩条件进行了计算．结果表明：（１）随着火心距离的增大，火星磁层中Ｏ＋离子的密度和通量密度沿磁力线都呈现出下降趋势；（２）随着Ｚ坐标的增大，火星磁层中Ｏ＋离子的密度和通量密度先呈现出下降趋势，后又逐渐上升；（３）火星的内禀磁场越强，Ｏ＋离子的密度和通量密度沿磁力线下降得越快；（４）在火星磁尾一定距离处，Ｏ＋离子的密度和通量密度随磁矩的增大而减小．这样，可通过探测火星磁层中离子的密度和通量密度分布来确定火星内禀磁场的强弱

A THEORETICAL STUDY OF THE DISTRIBUTION OF O IONS IN MARTIAN MAGNETOSPHERE

A model is developed to study the distribution of the O ions originating from the Martian ionosphere along the magnetic field lines on noon midnight meridian plane of Mars. The intensities of the magnetic field are calculated by considering the Martian magnetic field consisting of a dipole intrinsic field, which has different moments and a tail like induced field. The results show that: (1) the density and flux of the ions along the field line in the Martian magnetosphere decrease when Mars central distance increases; (2) with the increase of Z, the density and the flux of the ions are decreasing, and then increasing; (3) the larger the Martian magnetic moment is, the more quickly the density and flux decrease with the increase of Mars center distance; (4) the level of the ion density and flux are decreasing with the increase of Martian magnetic moment. Thus, the Martian intrinsic moment can be determined by analyzing the observed ion distribution.