Search results for "Electrojet"
showing 4 items of 4 documents
Correlation dimension and affinity of AE data and bicolored noise
1993
This paper is concerned with the general question of the dynamics of the magnetosphere. In general, to solve the dynamics of the magnetosphere one has to solve magnetohydrodynamic equations with some appropriate set of boundary conditions. This results in a very complex solution, which gives indications of being chaotic. The question of the chaotic nature of the magnetospheric dynamics has been addressed by various authors by looking at the correlation dimension of the auroral electrojet index. There has been disagreement on the outcome of such experiments, so the authors report on a detailed analysis of the auroral electrojet index time series. They find a correlation dimension of 3.4. For…
Characteristic time scale of auroral electrojet data
1994
The structure function of the AE time series shows that the AE time series is self-affine such that the scaling exponent changes at the time scale of approximately 113 (±9) minutes. Autocorrelation function is shown to have scaling properties similar to those of the structure function. From this result it can be deduced that the time scale at which the scaling properties of the AE data change should equal the typical autocorrelation time of these data. We find the typical autocorrelation time of the AE data is 118 (±9) minutes. The characteristic time scale of the AE data appears as a spectral break in their power spectrum at a period of about twice the autocorrelation time.
Sun-Earth System Interaction studies over Vietnam: an international cooperative project
2006
International audience; During many past decades, scientists from various countries have studied separately the atmospheric motions in the lower atmosphere, in the Earth's magnetic field, in the magnetospheric currents, etc. All of these separate studies lead today to the global study of the Sun and Earth connections, and as a consequence, new scientific programs (IHY- International Heliophysical Year, CAWSES- Climate and Weather in the Sun-Earth System) are defined, in order to assume this new challenge. In the past, many scientists did not have the possibility to collect data at the same time in the various latitude and longitude sectors. Now, with the progress of geophysical sciences in …
Comparison of the dynamics of the AU and PC indices
1998
The properties of AU and PC data were analyzed with different methods. It is shown that the dynamical behavior of the AU and PC time series, as analyzed by the structure function (SF), are very similar, while the SF of the AL time series shows different behavior. The SF of the AL data has a slope of 0.5 up to about 2 hours, after which it quickly decreases to about 0.1. On the other hand the slope of the SFs of AU and PC data continuously decreases to about 0.2, and in a longer time scale. It is suggested that the dissipative auroral electrojet currents have a characteristic time scale of 2 hours, and this underlies the AL dynamics. In contrast with this, the nondissipative Hall currents th…