Detailed study of Pi2 damped oscillations from low latitude magnetic observatory

• Published in: Journal of atmospheric and solar-terrestrial physics 2017-03, Vol.155, p.12-21
• Main Authors: Bulusu, Jayashree, Arora, Kusumita, Nagarajan, Nandini
• Format: Article
• Language: English
• Subjects: Magnetic substorms; Pi2 pulsations; Quiet time Pi2 pulsations
• ISSN: 1364-6826; 1879-1824
• DOI: 10.1016/j.jastp.2017.01.002

The study of low latitude damped Pi2 oscillations (40–150s) are investigated using archived data from Choutuppal (CPL), geomagnetic observatory, operated by CSIR-NGRI, Hyderabad, India. The period of investigation is during solar cycle 21 (1975–1983). All the Pi2 events identified during this period are subjected to detailed analysis for their association with substorm and non-substorm events. It is interesting to note that there is equal probability of occurrence of Pi2s with or without a substorm. The Pi2 frequencies associated with substorms showed an increased value in the post-midnight sector than compared to the Pre-midnight sectors. The non-substorm Pi2s are seen to be associated with lower levels of geomagnetic activity. The corresponding period of Pi2s decreases with increasing level of activity. While the generation of Pi2s are generally attributed to substorm onset, it is seen that the quiet time non-substorm events are related to plasmaspheric cavity mode resonances at low latitudes. •Detailed investigation of Pi2s associated with substorms at low latitudes.•Occurrence of pi2s during substorm and non substorm events.•Higher periods of Pi2s for very quiet geomagnetic conditions.•Generation mechanism of pi2s during extremely quiet geomagnetic conditions.