Bursts of geomagnetic pulsations and their relationship with dayside auroral forms

The relationship between geomagnetic pulsations and midday auroral activity has been investigated based on data obtained at the high latitude stations Barenzburg and Ny Ålesund, Spitzbergen. It is shown that in the region of red-dominated midday aurora, geomagnetic pulsations are observed with enhanced spectral features within periods of 1–10 s. A sharp, short-lived (3–5 min duration) increase of the magnetic pulsation amplitude up to 0.3–0.4 nT has been recorded. The increase of geomagnetic pulsation amplitude, as a rule, coincides with a sharp intensification of the auroral intensity, especially in the 557.7 nm emission. The Increase of the geomagnetic pulsation amplitude occurs during the initial period of the formation of bright discrete poleward-moving auroral arcs and/or during sharp intensity enhancements. Variations of the daytime discrete auroral arc luminosity with period 4–10 s and their correlation with geomagnetic pulsations have been documented.