  Low-energy ions of ionospheric origin constitute a significant contributor to
the magnetospheric plasma population. Measuring cold ions is difficult though.
Observations have to be done at sufficiently high altitudes and typically in
regions of space where spacecraft attain a positive charge due to solar
illumination. Cold ions are therefore shielded from the satellite particle
detectors. Furthermore, spacecraft can only cover key regions of ion outflow
during segments of their orbit, so additional complications arise if continuous
longtime observations, such as during a geomagnetic storm, are needed. In this
paper we suggest a new approach, based on a combination of synoptic
observations and a novel technique to estimate the flux and total outflow
during the various phases of geomagnetic storms. Our results indicate large
variations in both outflow rates and transport throughout the storm. Prior to
the storm main phase, outflow rates are moderate, and the cold ions are mainly
emanating from moderately sized polar cap regions. Throughout the main phase of
the storm, outflow rates increase and the polar cap source regions expand.
Furthermore, faster transport, resulting from enhanced convection, leads to a
much larger supply of cold ions to the near-Earth region during geomagnetic
storms.
