Abstract. We have investigated the total O + escape rate from the dayside open polar region and its dependence on geomagnetic activity, specifically Kp. Two different escape routes of magnetospheric plasma into the solar wind, the plasma mantle, and the high-latitude dayside magnetosheath have been investigated separately. The flux of O + in the plasma mantle is sufficiently fast to subsequently escape further down the magnetotail passing the neutral point, and it is nearly 3 times larger than that in the dayside magnetosheath. The contribution from the plasma mantle route is estimated as ∼ 3.9×10 24 exp(0.45 Kp) [s −1 ] with a 1 to 2 order of magnitude range for a given geomagnetic activity condition. The extrapolation of this result, including escape via the dayside magnetosheath, indicates an average O + escape of 3 × 10 26 s −1 for the most extreme geomagnetic storms. Assuming that the range is mainly caused by the solar EUV level, which was also larger in the past, the average O + escape could have reached 10 27-28 s −1 a few billion years ago. Integration over time suggests a total oxygen escape from ancient times until the present roughly equal to the atmospheric oxygen content today.

One of the most prominent (and potentially dangerous) features of space weather are geomagnetically induced currents, commonly known as GICs. The understanding of GICs is a major concern in order to preserve the power and communication systems and other technology on the ground. GICs are currents induced by rapid fluctuations in the Earth's magnetic field in any extended conducting technological infrastructure and can lead to malfunction or black outs of high-voltage power transmission systems (

We present 2 years of observations of ≥6 nT/s magnetic perturbation events (MPEs) from 5 high latitude Arctic stations. Most MPEs occurred within 30 min of a substorm onset, but substorms were neither necessary nor sufficient to cause MPEs. Premidnight and postmidnight MPEs had different temporal relations to substorms and occurred at slightly different latitudes.