Search

We have developed and examined a new regional geomagnetic index AES-80, defined similarly to the classical auroral electrojet AE index, using data from five Antarctic stations located at corrected geomagnetic latitudes about 80 °S. Because only sparse ground-based information can be derived from auroral latitudes in the Southern Hemisphere, and because no index comparable to AE can be constructed from locations in the south, the possibility of using AES-80 as a measure of high latitudes and polar cap activity is investigated. As a global average activity level indicator, it is found that in general AES-80 gives results rather similar to the classical AE index. However AES-80 provides a more robust measure of the occurrence of high-latitude geomagnetic activity.Key words. Magnetospheric physics (auroral phenomena; polar cap phenomena).

A new portable magnetometer theodolite with fluxgate sensor has been developed for measuring the components of the earth’s magnetic field. With this instrument, used as a null detector, it is possible to make absolute measurements of declination (D) and inclination (I). The compensation of the main magnetic field allows direct intensity measurements (H, X, Y, Z components); in this case the calibration is made by reference to a proton magnetometer.

Pc5 pulsations which were excited during the great magnetic storm of March 24, 1991 are analysed using the data from three French observatories located in the southern Indian Ocean at the subauroral and middle latitudes. The unusual strong Pc5 pulsations observed display features depending on the interval of occurrence: a quasi-noisy regime in the frequency range of 2.5–3.2 mHz characterizes the 04–10 UT interval, whereas the oscillations are nearly monochromatic with spectral maximum around 1.8–1.9 mHz in the 10–14 UT interval. The sharp change occurring at 10.17 UT could be associated to a sharp change in the magnetosphere structure or dynamics.

We present the overall strategy used to upgrade 9 former USSR observatories to INTERMAGNET standards. The following aspects are discussed: application for funding to the INTAS European ad-hoc agency, choice of observatories to upgrade, choice of the instrumentation to purchase and to install, calibration of the instrumentation and used standards, back-ups, installation of the instrumentation and observatory real estate upgrade, acquisition and communication, training of the observers and documentation, evaluation of the upgrades and management of the project. Several observatories were successfully upgraded and we expect their INTERMAGNET certification soon.