Following a given classi®cation of geomagnetic activity, we obtained aa index values for the Maunder minimum (1645±1715). It is found that the recurrent and ̄uctuating activities were not appreciable and that the shock activity levels were very low. The aa index level was due almost entirely to the quiet days. Calculated average solar-wind velocities were 194.3 km s from 1657 to 1700 and 218.7 ...

This study presents a fusion of data-driven and physics-driven methodologies of energetic electron flux forecasting in the outer radiation belt. Data-driven NARMAX (Nonlinear AutoRegressive Moving Averages with eXogenous inputs) model predictions for geosynchronous orbit fluxes have been used as an outer boundary condition to drive the physics-based Versatile Electron Radiation Belt (VERB) code...

Alfvén waves have been proposed as an important mechanism for the heating of the Sun's outer atmosphere and the acceleration of solar wind, but they are generally believed to have no significant impact on the Earth's upper atmosphere under quiet geomagnetic conditions due to their highly fluctuating nature of interplanetary magnetic field (i.e., intermittent southward magnetic field component)....

Usually, ionospheric Total Electron Content (TEC) variation with time can be viewed as a stationary random process under quiet conditions. However, sudden events of the Sun and the Earth such as solar flare and sudden commencement of geomagnetic storms may induce the disturbances of the ionosphere, so that the stationary random process is broken; the statistical model parameters change much. Ba...

abstract   background: postural instability has been identified as a potential precursor of falls in elderly subjects. postural stability in quiet stance is commonly assessed with center of pressure (cop) measures. the purpose of this study was to determine testretest reliability and minimal detectable change (mdc) for the center of pressure (cop) measures in the elderly subjects.   methods: ei...

Controlled experiments with dedicated ground-based ELF/VLF (0.3–30 kHz) transmitters are invaluable in investigating nonlinear whistler mode wave-particle interactions in the Earth’s magnetosphere. The most productive such experiment operated between 1973 and 1988 near L= 4 at Siple Station, Antarctica. A major effort has been undertaken to digitize and preserve a significant portion of the his...

Global ionospheric total electron content (TEC) is generally derived with ground-based Navigation Satellite System (GNSS) observations based on mathematical models in a solar-geomagnetic reference frame. However, are not well-distributed. There lack of over sparsely populated areas and vast oceans, where the accuracy TEC derivation reduced. Additionally, modified dip (modip) latitude more suita...