S_q发电机电流的UT变异性及其地面磁场的重建

UT-VARIABILITY OF THE Sq DYNAMO CURRENT AND ITS GROUND MAGNETIC FIELD RECONSTRUCTION

本文用不同经度的7对中低纬台站水平磁场分量H,求得1965年随世界时(UT)变化的S_q指数(一种描述S_q电离层发电机电流强度的地磁指数).结果表明,S_q发电机电流不仅有显著的逐日变化,而且有很大的UT变化.UT变化主要表现在电流总强度的强弱和电流涡焦点纬度移动两方面,这意味着决定发电机过程的太阳潮汐风场和电离层电导率随UT而变.用求得的S_q指数重新构造出的S_q变化与观测值符合得较好,它不仅显示出S_q幅度逐日变化的特点,而且还能复现出S_q形态的某些逐日变异性.

The data of geomagnetic horizontal component H obtained at 7 pairs of stations are used to calculate Sq index, a new geomagnetic index describing the intensity of the Sq dynamo current. Besides remarkable day-to-day variability, UT-variation in Sq index has been found, implying changes both in the total intensity of the Sq dynamo current and in the focus latitude. The ionospheric conductivity and solar tidal wind are principle factors controling the dynamo process in the ionosphere. The Sq variations can be reconstructed using obtained Sq indices and the monthly average X, variation. The reconstructed Sq, being fairly well in agreement with observed ones, show basic behaviours of the day-to-day variability in Sq daily range and some distortions in the Sq pattern.