GEOMAGNETIC INDICES ASY-H AND SYM-H AND THEIR RELATION TO INTERPLANETARY PARAMETERS

The dependences of the geomagnetic in-dices SYM-H and ASY-H on interplanetary parameters for the period from 1981 to 2015 according to their dai-ly averages are studied. The study is carried out in two ways: the first - the entire data array is analyzed, the second - the data are divided into 9 activity groups in accordance with the average daily values of the plane-tary geomagnetic index Ap. A correlation analysis of the indices with the solar wind speed, magnitude, and the north-south component of the interplanetary magnetic field (IMF) has been performed. The search for a rela-tionship between the ASY-H and SYM-H indices and interplanetary parameters turned out to be more success - ful when considering the entire data array than in the case of splitting the data into groups of magnetic activi-ty. Regression equations relating ASY-H and SYM-H to interplanetary parameters are determined. It has been found that when describing the relationship between the ASY-H and SYM-H indices and the IMF north-south component, it is necessary to take into account the con-tribution of the IMF modulus.