Service International des Indices Géomagnétiques
International Service of Geomagnetic Indices

Polar Cap (PC) Magnetic Activity indices

PCN, PCS time resolution: 1 minute (UT) interval
unit: mV/m
Available PCN: from 1975 onwards
PCS: from 1995 onwards
Type of index Polar Cap index horizontal component disturbances
Purpose To monitor the geomagnetic activity over the polar caps caused by changes in the interplanetary magnetic field (IMF) and solar wind, driven by the geoeffective interplanetary electric field irrespective of time, season and solar cycle.
Network Made of 2 polar cap stations.
(see list of actual and previous PC magnetic observatories)
Derivation The PC index is deduced (*) from the deviations in the horizontal H and D magnetic field components from the quiet level at two polar cap stations (Thule and Vostok for respectively the PCN and PCS).

(*) More specific and detailed information may be found on the PC-index website devoted to PC index.
ISGI Collaborating Institutes Arctic and Antarctic Research Institute (AARI, Russian Federation) and
the National Space Institute, Technical University of Denmark (DTU, Denmark)
IAGA endorsed IAGA 12th Scientific Assembly (Mérida, Yucatán, México) Resolution No. 3 (2013)
Historical references Description of IAGA endorsed PC index. Get PDF (99K)
• Janzhura, A., and O. Troshichev (2008) - Determination of the running quiet daily geomagnetic variation, J. Atmos. Solar-Terr. Phys., 70, 962-972.
• Janzhura, A., and O. Troshichev (2011) - Identification of the IMF sector structure in near-real time by ground magnetic data, Ann. Geophys., 29, 1491-1500.
• Stauning, P., O.A. Troshichev, and A. Janzhura (2006) - Polar Cap (PC) index. Unified PC-N (North) index procedures and quality, Scientific Report 06-04, Danish Meteorological Institute, Copenhagen, Denmark.
• Troshichev, O.A., N.P. Dmitrieva, and B.M. Kuznetsov (1979) - Polar cap magnetic activity as a signature of substorm development, Planet. Space Sci., 27, 217-221. • Troshichev, O., A. Janzhura, and P. Stauning (2006) - Unified PCN and PCS indices: Method of calculation, physical sense, and dependence on the IMF azimuthal and northward components, J. Geophys. Res., 111, A05208, doi:10.1029/2005JA011402.
• Troshichev, O., and A. Janzhura (2012) - Space Weather Monitoring by ground-Based Means: PC index, Springer Praxis Books, Berlin, 287 p.
• Vennerstrøm, S., E. Friis-Christensen, O.A. Troshichev, and V.G. Andrezen (1991) - Comparison between the polar cap index, PC, and the auroral electrojet indices AE, AL, and AU, J. Geophys. Res., 96, 101