Open Access

Automated detection of Pi 2 pulsations using wavelet analysis: 2. An application for dayside Pi 2 pulsation study

Earth, Planets and Space201451:BF03352206

https://doi.org/10.1186/BF03352206

Received: 9 December 1997

Accepted: 24 August 1998

Published: 6 June 2014

Abstract

We investigated statistical characteristics of dayside Pi 2 pulsations observed at Mineyama (25.5° geomagnetic latitude) from November 1994 through June 1996, using an algorithm to detect Pi 2 pulsations which was introduced in Part 1 of the accompanying paper. We obtained the following results. (1) The ratio of the number of Pi 2 pulsations on the dayside (06-18 MLT) to that on the nightside (18-06 MLT) was about 31%. (2) The polarization of the dayside Pi 2 pulsations changed from right-handed before local noon to left-handed after local noon. (3) Wave power of dayside Pi 2 pulsations in the H-component has a peak around local noon and dips on both dawn and dusk sides. (4) Frequency of the fundamental wave is ranging from 9 mHz to 30 mHz with dominant frequency of 17–24 mHz, and frequency ratios of the first three harmonics are 1: ( 1.7 ± 0.5): ( 2.3 ± 0.7 ). We found that the magnetospheric cavity model can explain most of these observational results.