Power grid disturbances and polar cap index during geomagnetic storms

The strong geomagnetic storm in the evening of 30 October 2003 caused high-voltage power grid disturbances in Sweden that expanded to produce hour-long power line outage in Malmö located in the southern part of the country. This was not a unique situation. The geomagnetic storm on 13 March 1989 caused extensive disruptions of high-voltage power circuits especially in the Province of Quebec, Canada, but also to a lesser degree in Scandinavia. Similar events have occurred earlier, among others, during the great storms of 13–14 July 1982 and 8–9 February 1986. These high-voltage power grid disturbances were related to impulsive magnetic variations accompanying extraordinarily intense substorm events. The events were preceded by lengthy intervals of unusually high values of the Polar Cap (PC) index caused by enhanced transpolar ionospheric convection. The transpolar convection transports magnetic flux from the dayside to nightside which causes equatorward displacements of the region of auroral activity enabling the substorms to hit vital power grids. During the 30 October 2003 event the intense solar proton radiation disabled the ACE satellite observations widely used to provide forecast of magnetic storm events. Hence in this case the alarmingly high PC index could provide useful warning of the storm as a back-up of the missing ACE-based forecast. In further cases, monitoring the PC index level could provide supplementary storm warnings to the benefit of power grid operators

Currents of quasi-trapped particles and their interaction with the geomagnetic field /symmetrical approximation/

Currents of quasitrapped particles and their interaction with geomagnetic fiel

Effective area for the northern polar cap magnetic activity index

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94783/1/grl12045.pd

The linear dependence of polar cap index on its controlling factors in solar wind and magnetotail

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94909/1/jgra21722.pd

Long‐term variation of driven and unloading effects on polar cap dynamics

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95078/1/jgra21680.pd

Invariability of relationship between the polar cap magnetic activity and geoeffective interplanetary electric field

The PC (polar cap) index characterizing the solar wind energy input into the magnetosphere is calculated with use of parameters α, β, and &phi;, determining the relationship between the interplanetary electric field (<i>E</i>_KL) and the value of magnetic activity &delta;<i>F</i> in the polar caps. These parameters were noted as valid for large and small <i>E</i>_KL values, and as a result the suggestion was made (Troshichev et al., 2006) that the parameters should remain invariant irrespective of solar activity. To verify this suggestion, the independent sets of calibration parameters α, β, and &phi; were derived separately for the solar maximum (1998–2001) and solar minimum (1997, 2007–2009) epochs, with a proper choice of a quiet daily variation (QDC) as a level of reference for the polar cap magnetic activity value. The results presented in this paper demonstrate that parameters α, β, and &phi;, derived under conditions of solar maximum and solar minimum, are indeed in general conformity and provide consistent (within 10 % uncertainty) estimations of the PC index. It means that relationship between the geoeffective solar wind variations and the polar cap magnetic activity responding to these variations remains invariant irrespective of solar activity. The conclusion is made that parameters α, β, and &phi; derived in AARI#3 version for complete cycle of solar activity (1995–2005) can be regarded as forever valid