O+ Ion upward motion at 1000 km altitude due to ambipolar electric fields

What is it about?

Ion upflow mechanisms at 1000 km altitude are examined using conjunctional observations from the e-POP satellite, the DMSP satellite, and the ground-based radars during low geomagnetic activity. Simultaneous measurements of very low ion temperature and low-energy (<1 keV) electron precipitation suggest that the observed large (>2.6 km/s) O+ ion upflow velocities are mainly due to ambipolar electric fields.

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Why is it important?

This study clarifies the mechanisms of O+ ion upflow at 1000 km altitudes, the whole process of which is very complicated in nature and contribute significantly to the magnetospheric processes that generate magnetic storms. The later poses threat to the airborne instruments as well as ground-based power grids and pipe lines. The O+ ion upflow velocities (>2.6 km/s) measured by the high-resolution (100 samples per second) ion detector e-POP SEI instrument during low geomagnetic activity are surprisingly large. These observations present the e-POP SEI instrument's ability to resolve ion field-aligned motion in very high resolution.