低纬低电离层中的不稳定性

低纬低电离层中的不稳定性 INSTABILITIES IN THE LOWER IONOSPHERE AT LOW—LATITUDE 刘选谋 first-author 刘曾厚 顾涛 崔荣 低电离层中,由于带电粒子同中性粒子间的碰撞,导致出现DC电场;同时因为地磁场的存在而感应出霍尔电流;加之电离层是部分电离的等离子体,其中存在电子密度的垂直梯度。在这些情况下,以上因素的共同效应导致了这一区域的不稳定性。本文从等离子体二流方程出发,导出了这种不稳定性的增长速率γ。对这种不稳定性进行的数值模拟表明,在扰动发生后150秒,低电离层中电子密度出现起伏,起伏的空间尺度为数百米至数公里量级,并有在水平和垂直方向移动的趋势。文中还对1980年2月16日云南日蚀期间所作的观测作了讨论。 The Collisions betwcen charged and neutral particles will lead to the ap-pearance of a DC electric field in the lower ionosphere and Hall current induced by Earth’s magnetic field will also appear.At the same time, the lower ionosphere is a plasma ionized partially and there is agradient of the electron density. Under these circumstances the combined effects of them will cause instabilities in this region. This paper deals with the growth rate γ of these instabilities which has been derived from the two-fluid plasma equations. In addition, our numerical simulation results indicate that iso-electron density contours in the lower ionosphere have some undulations 150 second after the initial disturbance, the spatial scale of which is of the order of several hun-dred meters to kilometers, and that there is a tendency for them to travel in the horizontal and vertical directions. In this paper the instability of the lower ionosphere observed during the solar eclipse on February 16, 1980 in Yunnan province is also discussed. 1984-02-01 2021-04-01 2