The quiet geomagnetic field at geosynchronous orbit and its dependence on solar wind dynamic pressure

Journal Article · Wed Jan 01 04:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/91JA02135· OSTI ID:5557566

Rufenach, C L; Schaper, J ^[1]; McPherron, R L ^[2]

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1. NOAA Space Environmental Lab., Boulder, CO (United States)
2. Univ. of California, Los Angeles (United States)

Vector magnetic fields at geosynchronous orbit were measured during 1980-1984 using the operational GOES 2, GOES 5, and GOES 6 spacecraft magnetometers. The authors corrected these spacecraft measurements for offsets due to spacecraft state and then used these field estimates to create a data base with 1-min resolution. Hourly quiet field values were calculated for these years from this data base using the ground-based geomagnetic index criteria AE < 120 nT and {vert bar}Dst{vert bar} < 20 nT. These quiet field components, rotated into dipole HVD coordinates, were approximated by the first two coefficients of a two-dimensional Fourier series in time of day and season. The quiet geosynchronous field components, to first order, are given by mean values of about 90 nT, {minus}60 nT, and 5 nT; and sinusoidal diurnal amplitudes of about 21 nT, 5 nT, and 5 nT, respectively, for H, V, and D where the spacecraft magnetometer was located near the geomagnetic meridian. The second harmonic diurnal amplitudes and the first and second harmonic seasonal amplitudes are typically of the order of a few nanoteslas or less except for the D component, which exhibits a larger seasonal variation. Furthermore, a one-dimensional Fourier series in time of day was used to study the quiet field dependence on solar wind dynamic pressure, P{sub d}, by indexing the measurements into five pressure ranges during 1980. These quiet H measurements, including the pressure dependence, are compared with a first-order field model superimposed with a tail current, resulting in magnetospheric currents (magnetopause and tail) in agreement with previous model values.

• OSTI ID: 5557566
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A1; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
&amp; Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CONFIGURATION
CURRENTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTRIC CURRENTS
FOURIER ANALYSIS
GEOMAGNETIC FIELD
GOES SATELLITES
INTERACTIONS
INTERPLANETARY MAGNETIC FIELDS
MAGNETIC FIELDS
MAGNETOPAUSE
MAGNETOTAIL
MORPHOLOGY
ORBITS
PLASMA PRESSURE
PRESSURE DEPENDENCE
RING CURRENTS
SATELLITES
SEASONAL VARIATIONS
SHAPE
SIZE
SOLAR ACTIVITY
SOLAR WIND
VARIATIONS