DMSP/F2 electron observations of equatorward auroral boundaries and their relationship to the solar wind velocity and the North-South component of the interplanetary magnetic field

Journal Article · Sun Nov 01 00:00:00 EST 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA086iA12p09961· OSTI ID:5797793

Hardy, D A; Burke, W J; Gussenhoven, M S; Heinemann, H; Holeman, E

Approximately 2500 equatorward boundaries of auroral electron precipitation were determined for times when hourly averages of the interplanetary magnetic field and solar wind velocity V were available. The equatorward boundaries were determined from data returned by the SSJ/3 electron detector on board the DMSP/F2 satellite in magnetic local sectors between 0400 and 1100 hours on the morningside of the oval and between 1500 and 2300 hours on the eveningside of the oval. The boundary data were separated into 1-hour zones in magnetic local time. Within each zone the boundary locations were studied as functions of B/sub z/ and B/sub z//sup 2/, VB/sub z/ and VB/sub z//sup 2/. Significant results were obtained when the boundaries were correlated with hourly average of B/sub z/ and VB/sub z/ for the hour preceding the one in which the boundary was measured and when the linear regression was performed separately for data points where B/sub z/< or =1 nT and B/sub z/>1 nT. For points where B/sub z/1 nT, the correlation with B/sub z/ and VB/sub z/ gave slopes generally between 0.8/sup 0/ and 1.2/sup 0//nT and between 1.5/sup 0/ and 2.5/sup 0//mV/m, respectively, with correlation coefficients of approx.0.7. The latitudes of the intercepts tend to decrease with increasing local time in the evening sector and with decreasing local time in the morning sector. In the range above 1 nT, the slope of the best fit line for correlation with B/sub z/, and VB/sub z/ changes sign. Slopes fall in the range -0.1/sup 0/ to -0.4/sup 0//nT and 0.21/sup 0/ to 1/sup 0//mV/m. Correlation coefficients are typically worse than -0.4. Correlations of the boundary with B/sub z//sup 2/ and VB/sub z//sup 2/ for both ranges of B/sub z/ are uniformly worse than those for B/sub z/ and VB/sub z/. The trend in slopes and intercepts with magnetic local time for B/sub z/< or =1 nT is found to be similar to that previously found for the correlation of the boundaries with Kp (Gussenhoven et al, 1981).

• Research Organization: Air Forace Geophysics Laboratory, Hanscom Air Force Base, Massachusetts 01731
• OSTI ID: 5797793
• Journal Information: J. Geophys. Res.; (United States), Vol. 86:A12
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL ZONES
ELECTRON PRECIPITATION
AURORAL OVAL
CORRELATIONS
INTERPLANETARY MAGNETIC FIELDS
MAGNETOSPHERE
PLASMA SHEET
SOLAR WIND
CHARGED-PARTICLE PRECIPITATION
EARTH ATMOSPHERE
MAGNETIC FIELDS
SOLAR ACTIVITY
640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)