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Postmidnight chorus: A substorm phenomenon
The ELF (10–1500 Hz) electromagnetic emissions in the midnight sector of the outer magnetosphere have been studied using Ogo 5 search coil magnetometer data. Chorus was detected in conjunction with
What is a geomagnetic storm
After a brief review of magnetospheric and interplanetary phenomena for intervals with enhanced solar wind-magnetosphere interaction, an attempt is made to define a geomagnetic storm as an interval
Two types of magnetospheric ELF chorus and their substorm dependences
Extremely low frequency (10–1500 Hz) magnetospheric chorus has been analyzed to investigate a possible dependence on substorms. Care was taken to separate spatial effects from temporal effects by
Interplanetary origin of geomagnetic activity in the declining phase of the solar cycle
Interplanetary magnetic field (IMF) and plasma data are compared with ground-based geomagnetic Dst and AE indices to determine the causes of magnetic storms, substorms, and quiet during the
The extreme magnetic storm of 1–2 September 1859
[1] The 1–2 September 1859 magnetic storm was the most intense in recorded history on the basis of previously reported ground observations and on newly reduced ground-based magnetic field data. Using
Lion roars and nonoscillatory drift mirror waves in the magnetosheath
A complete set of ISEE plasma wave, plasma, and field data are used to identify the plasma instability responsible for the generation of extremely low frequency (ELF) electromagnetic lion roars. Lion
Interplanetary origin of geomagnetic storms
Around solar maximum, the dominant interplanetary phenomena causing intense magnetic storms (Dst<−100 nT) are the interplanetary manifestations of fast coronal mass ejections (CMEs). Two
The Cassini Magnetic Field Investigation
The dual technique magnetometer system onboard the Cassini orbiter is described. This instrument consists of vector helium and fluxgate magnetometers with the capability to operate the helium device
A far ultraviolet imager for the International Solar-Terrestrial Physics Mission
The aurorae are the result of collisions with the atmosphere of energetic particles that have their origin in the solar wind, and reach the atmosphere after having undergone varying degrees of
Periodic variation in the geomagnetic activity : a study based on the Ap index
The monthly and daily samples of the Ap geomagnetic index for 51 years, 1932-1982, were investigated by means of the power spectrum technique. In general, the results confirm previous findings about