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Observations of Pi2 pulsations in a near ground state magnetosphere
Author(s) -
Sutcliffe P. R.
Publication year - 1998
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1998gl900092
Subject(s) - substorm , magnetosphere , latitude , solar wind , geophysics , quiet , geology , amplitude , equator , physics , atmospheric sciences , geodesy , plasma , astronomy , quantum mechanics
This paper reports on the observation of Pi2 pulsations under conditions with which they have not previously been associated, namely, extremely quiet solar wind conditions when the magnetosphere is in a near ground state. Three years of data were scanned for extremely quiet intervals on the basis of a p indices and solar wind parameters. Twenty‐four extremely quiet intervals were identified, thirteen of which contained Pi2 pulsation signatures at low latitudes. The Pi2 amplitudes were similar to those typically observed during substorm expansion phases. One interval was studied in greater detail. It exhibited other substorm signatures; however, the high latitude, negative, H‐component bay was extremely weak and spatially localized. During this interval Pi2 pulsations were also observed on the day side at low latitudes.