中文摘要：

由于电离层中分子性离子与电子的复合要比氧离子与电子的复合快得多，因此H2在电离层高度释放可有效地引起电子的消耗。本文基于一个包括中性气体扩散方程和离子化学反应方程的二维动力学模型，对H2在电离层高度释放过程进行了数值模拟研究，并分析了不同释放条件下的电子扰动特性。结果表明：1）500mol H2释放后，迅速向周围空间扩散，释放中心处的电子密度30S内下降了近4％，F2层临界频率下降了1％左右；2）在不同高度处释放H2时，最大的电子密度相对变化率并不是在峰值高度附近处释放时出现的；3）释放化学物质的量越多，电子密度的扰动幅度也越大，但两者之间并不存在线性关系；4）相同量的H2在电离层峰值高度处释放，白天的电子密度扰动幅度要大于夜间的扰动幅度。

英文摘要：

The recombination rate coefficients of molecular ion with electron are several orders greater than those of the dominant atomic oxygen ion in ionosphere F region, so the plasma densities in iono- sphere can be greatly depleted by modest amounts of H2 gas released at ionospheric altitudes. Based on a 2-D dynamics model including the neutral gas diffusion equation and the ion chemical reaction equa- tion, this paper simulates the processes of H2 released at ionospheric altitudes and analyzes the changes of ionospheric electron and foF2 （ critical frequency of F2 layer） at different temporal and spatial release conditions. Results show that： 1 ）500 mol H2 gas released at the ionospheric altitude diffuses swiftly, where the electron density decreases nearly 4% after 30 s and the foF2 （ critical frequency of F2 layer） decreases about 1% ;2 ）When the same amount of H2 is released at different altitudes ,the maximum rel- ative change rate of electron density will not appear when Hz is released nearby the peak altitude of F2 layer（ hmF2 ）;3 ）The more amount of Hz is released, the larger disturbance of electron density is caused, but there is not a linear relation between them ;4）The disturbance amplitude of electron density in daytime is larger than that in nighttime when the same amount of H2 released at hmF2.