earth online

Plasmapause Related boundaries in the topside Ionosphere as derived from Swarm Measurements


The Plasmapause Related boundaries in the topside Ionosphere as derived from Swarm Measurements (PRISM) is a project in response to the  Swarm DISC ITT 2.2 "Midlatitude Ionospheric Trough, Plasmapause and possibly related boundaries as determined from Swarm measurements".

The position of the plasmapause (PP) is a key parameter in space weather. The plasmapause is defined as the outer boundary of the Earth-corotating plasma (the plasmasphere) characterised by steep plasma density gradients. The variation of the PP location is a very sensitive indicator of geomagnetic activity. There are many space phenomena (e.g., cold plasma and energetic particle populations, etc.) separated spatially by the PP, as well as several space processes (e.g., high-latitude magnetosphere-ionosphere coupling processes, etc.) that are dynamically linked to the location of the plasmapause.

In project PRISM the team develop products that characterise PP related phenomena in the topside ionosphere. These are the mid-latitude ionospheric trough (MIT) based on electron density and temperature measurements of the Langmuir probe onboard and also from GPS TEC estimates, as well as the equatorward boundary of small-scale field-aligned currents leading to an index that can be used as an estimate of the midnight position of the plasmapause. The MIT equatorward/poleward edge is closely related to the ionospheric footprint of the PP/the auroral oval, respectively. The midnight PP index based on small-scale FAC signatures observed at low Earth orbit (LEO) altitudes. Both Swarm products, the MIT location and the midnight PP index, will be provided separately for the three individual Swarm satellites.

PRISM is a collaborative project between Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences, Germany and the Mining and Geological Survey of Hungary (Magyar Bányászati és Földtani Szolgálat, MBFSZ), Hungary.


Download project documents:


More information about PRISM project


Project duration: November 2019 – November 2020. PRISM is a project in response to the Swarm DISC as space is allowing.