Empirical relationship between interplanetary conditions and Dst

Journal Article · Sat Nov 01 04:00:00 EST 1975 · J. Geophys. Res., v. 80, no. 31, pp. 4204-4214

OSTI ID:4107184

Burton, R K; McPherron, R L; Russell, C T

An algorithm is presented for predicting the ground-based Dst index solely from a knowledge of the velocity and density of the solar wind and the north-south magnetospheric component of the interplanetary magnetic field. The three key elements of this model are an adjustment for solar wind dynamic pressure, an injection rate linearly proportional to the dawn-to-dusk component of the interplanetary electric field which is zero for electric fields below 0.5 mV m$sup -1$, and an exponential decay rate of the ring current with an e folding time of 7.7 hours. The algorithm is used to predict the Dst signature of seven geomagnetic storm intervals in 1967 and 1968. In addition to being quite successful, considering the simplicity of the model, the algorithm pinpoints the causes of various types of storm behavior. A main phase is initiated whenever the dawn-to-dusk solar magnetospheric component of the interplanetary electric field becomes large and positive. It is preceded by an initial phase of increased Dst if the solar wind dynamic pressure increases suddenly prior to the main phase. The recovery phase is initiated when the injection rate governed by the interplanetary electric field drops below the ring current decay rate associated with the ring current strength built up during the main phase. Variable recovery rates are generally due to additional injection during the recovery phase. This one algorithm accounts for magnetospheric behavior at quiet and at disturbed times and seems capable of predicting the behavior of Dst during even the largest of storms. (AIP)

• Research Organization: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90024
• NSA Number: NSA-33-018320
• OSTI ID: 4107184
• Journal Information: J. Geophys. Res., v. 80, no. 31, pp. 4204-4214, Journal Name: J. Geophys. Res., v. 80, no. 31, pp. 4204-4214; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

*MAGNETOSPHERE-- SOLAR WIND
640203* --Physics Research--Atmospheric Physics-- Magnetospheric Phenomena
DENSITY
ELECTRIC FIELDS
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
MAGNETIC STORMS
N58300* --Physics (Atmospheric)--Magnetospheric Phenomena
RING CURRENTS
SOLAR FLUX
VELOCITY