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As a contribution to the International Magnetospheric Study the University of Munster has installed an array of 32 Gough-Reitzel type magnetometers located mostly in Northern Scandinavia. Also for the IMS, the Max Planck Institute for Aeronomy at Lindau is operating the Scandinavian Twin Auroral Radar Experiment (STARE) which consists of two nearly identical backscatter radars located near Trondheim (Norway) and Sauvamaki (Finland). For a weak isolated substorm on October 7, 1976 the spatial structure of the electron density irregularities observed by the Trondheim-radar and the equivalent current distribution derived from the magnetic measurements have been compared. A good correspondence has been found between the location and magnitude of the maxima of the horizontal magnetic disturbance and the radar backscatter amplitude for an eastward electrojet. For most of the comparison there appeared also to be good agreement between the direction of the equivalent current and the direction antiparallel to the line-of-sight irregularity drift. This supports the idea that the backscatter irregularities are caused by current driven plasma instabilities and that it is possible to determine auroral ionospheric currents with the backscatter radar technique. However, during periods of enhanced electron precipitation, differences between the drift directions given by the two methods were observed.           ARK: https://n2t.net/ark:/88439/y099827 Permalink: https://geophysicsjournal.com/article/250 &nbsp

The substorm on 2 March 1978 was selected for study as a relatively weak substorm, starting at about local magnetic midnight, that could be observed with instruments in Northern Scandinavia. The analysis is based on a comparative study of data from the IMS magnetometer network, all-sky cameras, pulsation magnetometers, and riometers in the Scandinavian area. In addition other data are used to support the results, e.g., a photograph from the DMSP-F2 satellite, showing the auroral situation over Scandinavia, and further west, immediately after the substorm onset. The substorm was preceded by a weak activation of aurora and magnetic disturbance about 3 min before the onset. After a fading that lasted for 20 s and could be observed only in optical aurora, the substorm onset led to a strong brightening of the aurora, an enhancement of the westward electrojet, a sudden rise in the ionospheric D-layer absorption, and Pi B type pulsations. Immediately after the onset, the ground magnetic data suggest the appearence of a pair of oppositely directed, localized, field-aligned currents (FACs). The main development of the signatures of the downward FAC was clearly delayed by about 3 min. There were significant correlations between the magnetic signatures of the two FACs and different features and spectra of the optical aurora, both in time and location. The observed Pi B type pulsations lasted as long as a growth in the local onset-connected FACs could be inferred. Within the first three minutes the localized three dimensional current system developed into a more sheet-like configuration. An expansion to the west, possibly accompanied by a westward travelling surge, was traced with riometers and magnetometers on Iceland and Greenland.           ARK: https://n2t.net/ark:/88439/y084828 Permalink: https://geophysicsjournal.com/article/208 &nbsp

A two-dimensional magnetometer array was progressively installed in Scandinavia, from 1974 onwards, for operation during the IMS period (1977-1979). The 36 instruments, which are buried in the ground, are of the Gough-Reitzel type, i.e., classical magnetometers, with wire-suspended magnets and optical recording. The time-variation period range observable is from about 50 s to several days. In northern Scandinavia, the spacing between the stations is about 100-150 km in both the north-south and east-west directions. For presentation and analysis of the data a special Cartesian coordinate system has been introduced (the 'Kiruna system'). It is derived by mapping the local Earth's surface onto a tangential plane, with its origin close to Kiruna (geographic coordinates 67.8 N, 20.5 E). First results from some stations show that internal contributions to the recorded horizontal geomagnetic variations are small and possibly negligible at lower frequencies. However, at frequencies above about 2 mHz the variations of the vertical component display a strong amplification near the coast, and indicate the existence of conductivity anomalies at some inland locations. In order to demonstrate the observational capabilities of the array, equivalent overhead current configurations are presented which characterize a substorm recorded on October 7, 1976.           ARK: https://n2t.net/ark:/88439/y001456 Permalink: https://geophysicsjournal.com/article/160 &nbsp