Accession Number : AD0763388

Title :   The Relation between the Azimuthal Component of the Interplanetary Magnetic Field and the Geomagnetic Field in the Polar Caps,

Corporate Author : STANFORD UNIV CALIF INST FOR PLASMA RESEARCH

Personal Author(s) : Svalgaard,Leif

Report Date : MAY 1973

Pagination or Media Count : 50

Abstract : The recently discovered relation between the azimuthal component of the interplanetary magentic field and magnetic variations in the earth's polar caps is reviewed. When the IMF azimuthal component is positive (typical of an interplanetary sector with magnetic field directed away from the sun) geomagnetic perturbations directed away from the earth are observed within 8 degrees from the corrected geomagnetic pole. When the IMF azimuthal component is negative (typically within toward sectors) the geomagnetic perturbations are directed towards the earth at both poles. These perturbations can also be described by an equivalent current flowing at a constant magnetic latitude of 80 degrees - 82 degrees clockwise around the magnetic poles during towards sectors and counterclockwise during away sectors. This current fluctuates in magnitude and direction with the azimuthal component of the IMF, with a delay time of the order of 20 minutes. The importance of this effect for our understanding of both solar magnetism and magnetospheric physics is stressed in view of the possibility for investigating the solar sector structure during the last five sunspot cycles. (Author)

Descriptors :   (*GEOMAGNETISM, POLAR REGIONS), MAGNETIC FIELDS, DIURNAL VARIATIONS, MAGNETIC STORMS, TELLURIC CURRENTS, MAGNETOSPHERE, SOLAR WIND

Subject Categories : Atmospheric Physics
      Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE