First results from a closely-spaced induction coil magnetometer array in Svalbard

Induction coil magnetometers have recently been installed in Svalbard to form a high-latitude, closely-spaced array. These instruments have been installed on Svalbard primarily because it is the only readily accessible site in the northern hemisphere at which the ionospheric footpoint of the magnetospheric cusp is consistently in darkness during winter solstice. Magnetic field lines from the cusp region map to the outer boundary of Earth's magnetosphere, where it interacts with the solar wind and interplanetary magnetic field (IMF). Because of this, ground stations located under the cusp region can provide information about the first entry of energy and momentum from the solar wind to Earth's ionosphere. Search coil instruments provide much better signal to noise ratios than fluxgate magnetometers in the middle and upper ULF frequency range (0.02 - 5 Hz), which includes Pc 3 and Pc 1-2 pulsations and irregular Pi 1 activity. Deployment of this closely-spaced two-dimensional array of search coil instruments, each with accurate GPS timing, allows the determination of phase differences between such signals observed at different sites, and hence can provide apparent propagation directions to infer wave source locations. We thus can expect to identify wave source locations with specific magnetospheric regions, such as plasma sheet, low latitude boundary layer, cusp proper, or plasma mantle, with more confidence and reliability than in earlier studies at other locations. In this presentation, early results of the observations, showing both narrow- and broadband signatures, are presented and discussed.