A new dataset of Swarm Langmuir probe Ion Drift, density and effective Mass (SLIDEM) at 2 Hz cadence is now available for the three Swarm spacecraft on the Swarm dissemination server.

The main data products are: estimates of along-track ion drift at high latitudes, estimates of effective ion mass at low and mid latitudes and an ion density estimate for all latitudes. The measurements make use of Electric Field Instrument faceplate current measurements, and are thus available only when the EFI faceplate is set to -3.5 V, expected to be complementary to the TII cross-track ion drift data.

Effective ion mass is highly sensitive to variations in even small concentrations of light ions like hydrogen and thus may be of particular interest to those investigating low to mid-latitude ionospheric dynamics and composition.

The density estimate incorporates faceplate current measurements into the standard Level 1b LP density calculation to remove the assumption of pure oxygen ions at low latitudes and the assumption of a stationary ionosphere at high latitudes. Users are encouraged to assess the new dataset for quality and validity and to use it in scientific studies. The University of Calgary EFI team may be contacted for questions about data quality and interpretation.

The dataset covers the time interval from 2 October 2014 to 18 October 2021.

The dataset is available on the Swarm dissemination server at the following path:

/ Advanced/Plasma_Data/2_Hz_Ion_Drift_Density_and_Effective_Mass_dataset/

For more information on the contents of this data product, please refer to the SLIDEM Product Definition document.