ULTRA-LOW FREQUENCY GEOMAGNETIC PULSATIONS OBSERVED AT MID LATITUDES IN PANAGJURISTE, BULGARIA

Chamati, M.; Andonov, B.
Abstract:
The spectral characteristics of the ULF waves (1mHz -1Hz) provide useful information about the conditions in the solar wind and in the magnetosphere. A series of geomagnetic field variations data are collected by the tri-axial search-coil instrument and acquisition system located at Panagjuriste, Geomagnetic Observatory (PAG), Bulgaria and other series of data are collected from two different instruments located at Conrad Observatory (WIC), Austria and Ebro Observatory (EBR), Spain, which operate within INTERMAGNET - the global network of geomagnetic observatories. We analyze the time series corresponding to the period 00 - 01 UT (02-03 LT) on 29 December 2020. To determine the spectral characteristics of observed geomagnetic pulsations, we apply the autocorrelation analysis to obtain the autocorrelation function and the power spectra, as well as Morlet wavelet analysis of the considered time series. Pulsations with an amplitude modulation period of about 15 min. (~900 s.) and main periods at 84, 75 and 68 seconds are determined. The specific spectral characteristics of these pulsations are obtained on the basis of the Morlet dynamic spectra. They show continuous ULF pulsations represented in four wave “packets” of sinusoidal oscillations with varying periods from 30 seconds till 115 seconds and main periods at 84 s., 75 s. and 68 seconds. We conclude that the recorded pulsations at Geomagnetic Observatory Panagjuriste, Bulgaria, located at mid latitudes, on 29 December 2020 during the time interval 00-01 UT are continuous ULF pulsations within the range Pc4 (45-150 seconds). Similar ULF continuous pulsations in the Pc4 range, with similar power spectra during the same time are observed both at Ebro and Conrad Observatories.
SGEM Research areas:
Year:
2021
Type of Publication:
In Proceedings
Keywords:
ULF; pulsations; geomagnetic field; Panagjuriste
Editor:
• Prof. DSc. Oleksandr Trofymchuk, UKRAINE • Prof. Dr. hab. oec. Baiba Rivza, LATVIA
Volume:
21
SGEM Book title:
21st International Multidisciplinary Scientific GeoConference SGEM 2021
Book number:
1.1
SGEM Series:
SGEM International Multidisciplinary Scientific GeoConference
Pages:
587-594
Publisher address:
51 Al. Malinov blvd, Sofia, 1712, Bulgaria
SGEM supporters:
SWS Scholarly Society; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Serbian Acad Sci & Arts; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; European Acad Sci, Arts & Letters; Acad Fine Arts Zagreb Croatia; Croatian Acad Sci
Period:
16 - 22 August, 2021
ISBN:
978-619-7603-20-0
ISSN:
1314-2704
Conference:
21st International Multidisciplinary Scientific GeoConference SGEM 2021, 16 - 22 August, 2021
DOI:
10.5593/sgem2021/1.1/s05.104
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