The Swarm (ESA's Earth Observation constellation mission) Level 2 time series of field-aligned and radial current densities along the orbit using the dual-satellite method for the Swarm lower satellite pair A and C are provided. Field-aligned current (FAC) density is derived by multiplying the radial current (IRC) density with the inclination angle of the geomagnetic field. This can be calculated for latitudes where the magnetic field is well inclined (|I| > 30°). In areas near the magnetic equator where the magnetic inclination angle is less than 30° (|I| < 30°), the FAC values are set to NaN. The radial current density can be calculated for the entire orbit, except for latitudes above 87° (near the poles), where both FAC and IRC values are set to NaN.

It is important to note that for this time series provided here, the magnetic field data used for the dual-satellite method is not low-pass filtered with a 3-dB cutoff period of 20 seconds (corresponding to a wavelength of 150 km) as described in the "swarm-level-2-fac-dual-product-description" document. Additionally, FAC and IRC values are set to NaN when the integration area becomes smaller than 3e8 m^2, and no daily CDF files are produced if the along-track time difference between two Swarm satellites (A and C) exceeds 11 seconds.

The data is provided in NASA CDF format and can be accessed at ftp://isdcftp.gfz-potsdam.de/swarm/OPER/Level2/FAC_TMS/Sat_AC/small_scale. The output variable description is available at https://swarmhandbook.earth.esa.int/catalogue/SW_FAC_TMS_2F.