Poynting vectors of Pc 5 pulsations observed by the GEOTAIL satellite in the dayside outer magnetosphere

Abstract

Poynting vectors of Pc 5 pulsations observed in the dayside outer magnetosphere are examined with the magnetic and electric field data simultaneously observed by the GEOTAIL satellite. Poynting energy can be estimated as about 10−8–10−6 W/m2 in both directions across and along the magnetic field-line. However, the energy propagating across the magnetic field-line is larger than the energy propagating along the magnetic field-line. From this result we can estimate the Pc 5 wave energy flowing into the inner magnetosphere during an hour as 1010–1013 J, which is one or two orders less than the substorm energy (about 1014–1015 J). However, by taking into account of the continuous activation of Pc 5 pulsations in the outer magnetosphere, Pc 5 waves should play an important role for energetics in the magnetosphere.