Characteristics of low-latitude whistlers and their relation with f0F2 and magnetic activity

Characteristics of low-latitude whistlers observed with instrumentation at three locations in China over a three-year period are discussed. The whistler maxima were always detected after midnight, local time, and none occurred during the daytime or evening. The rate of occurrence at the three sites was less than 1/min. A similarity was found between the diurnal variation of the median value of the critical frequency of the F2 region and that of the whistler dispersion. A set of algebraic equations was employed to calculate the electron concentration in the equatorial plane at the top of the propagation path (Neq) and the tube content (NT). The whistler dispersion and f0F2 (the critical frequency) were then converted into Neq and NT, resulting in calculated median values which agreed with satellite observations. Finally, a positive correlation was obtained between the daily variation of Kp and whistler dispersion, supporting the hypothesis that the whistler occurrence rate at low latitudes peaks one or two days after a geomagnetic storm day