A revised version of the storm-time disturbance index D st is calculated using hourly-mean magnetic-observatory data from four standard observatories and collected over the years 1958–2007. The calculation algorithm is a revision of that established by Sugiura et al., and which is now used by the Kyoto World Data Center for routine production of D st. The most important new development is for t...

This paper reports, for the first time on a statistical basis, key role played by Alfvénic fluctuations in modulating recovery phase of geomagnetic storms, slowing down restoration magnetosphere toward its pre-storm equilibrium state. Using interplanetary and measurements collected over more than one solar cycle, high correlation between durations streams concurrent phases is found, pointing to...

Geomagnetic storm-detection algorithms are important for space-weather-warning services to provide reliable warnings (e.g., ionospheric disturbances). For that reason, a new approach using an adaptive filter (least mean squares algorithm) the detection of geomagnetic storms based on volatility north–south interplanetary magnetic field Bz is presented. The not dependent solar wind plasma measure...

There is an increasing amount of evidence linking biological effects to solar and geomagnetic disturbances. A series of studies is published referring to the changes in human physiological responses at different levels of geomagnetic activity. In this study, the possible relation between the daily variations of cosmic ray intensity, measured by the Neutron Monitor at the Cosmic Ray Station of t...

Absfract-Stetlar ultraviolet light near 1SOOA is attenuated in the Earth’s upper atmosphere due to strong absorption in the Schumarm-Runge continuum of molecular oxygen. The intensity of stars in the Schumann-Runge continuum region has been monitored by the University of Wisconsin stellar photometers aboard the OAO-2 satellite durin ‘I, occultation of the star by the Earth’s atmosphere. These d...

This paper studies the ionospheric response to a major geomagnetic storm of October 18-19, 1995, using the thermosphere-ionosphere electrodynamics general circulation model (TIEGCM) simulations and the global ionospheric maps (GIM) of total electron content (TEC) observations from the Global Positioning System (GPS) worldwide network. The TIE-GCM results, which utilize the realistic time-depend...

During emergency events, we could significantly depend on the stable operation of radio communication, navigation, and radars. The ionosphere, especially its auroral regions, influences systems, which is why scientists engineers create systems to monitor these regions. Using data from global GNSS network, analyzed 10 strongest magnetic storms solar cycle 24: five coronal mass ejection-driven (C...

The strong increase in the ̄ux of relativistic electrons during the recovery phase of magnetic storms and during other active periods is investigated with the help of Hamiltonian formalism and simulations of test electrons which interact with whistler waves. The intensity of the whistler waves is enhanced signi®cantly due to injection of 10±100 keV electrons during the substorm. Electrons which...