HR: 0830h
AN: SH21B-0108    [PDF]
TI: NEW GEOMAGNETIC INDEX (IDV) MEASURING MAGNITUDE OF INTERPLANETARY MAGNETIC FIELD
AU: * Svalgaard, L
EM: agu@leif.org
AF: Easy Toolkit, Inc., 6927 Lawler Ridge, Houston, TX 77055 United States
AU: Cliver, E W
EM: cliver@plh.af.mil
AF: Air Force Research Laboratory, Hanscom Air Force Base, Bedford, MA 01731 United States
AB: We present a new long-term geomagnetic index (the IDV index) which has the property that it is a proxy of the magnitude of the interplanetary magnetic field at the Earth. The index is constructed (for any given station) as the monthly (or yearly) average of the differences (taken without regard to sign) of the hourly mean values of the hour following local midnight between two consecutive days. It is similar to the classical u-measure except that the differences are between one-hour values rather than daily means. The IDV index has a strong correlation (r=0.88) with the magnitude, B, of the IMF, but is uncorrelated (r=0.09) with the solar wind speed, V. Because other indices (e.g. aa and our own IHV) are strongly correlated with BV**2, the IDV index fords a way of separating the influence of B and V and thus determining both.
DE: 1555 Time variations--diurnal to secular
DE: 2134 Interplanetary magnetic fields
DE: 2784 Solar wind/magnetosphere interactions
DE: 2794 Instruments and techniques
DE: 7537 Solar and stellar variability
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting