Radar and satellite observations of the storm time cleft

Technical Report · Wed Aug 01 04:00:00 EDT 1990

OSTI ID:6256888

Yeh, H C; Foster, J C; Holt, J M; Redus, R H; Rich, F J

During the magnetic storm of February 8-9, 1986, the region of strong ion convection in the vicinity of the dayside cusp expanded equatorward into the field of view of the Millstone Hill radar at lower mid-latitudes. High-speed (>1.5 km/s) poleward ion flows were found at latitudes as low as 60 deg invariant latitude, at least 10 deg lower than the typical cleft/cusp position for moderately disturbed (Kp>4) magnetospheric conditions. The ion velocity pattern responded promptly to changes in the interplanetary magnetic field By direction. The large-scale two-dimensional convection pattern across the dayside was well resolved using radar azimuth scan data at Millstone Hill, thus enabling us to place the fine-scale radar/satellite observations of the storm time cusp and cleft in the context of the large-scale pattern. We present a detailed comparison of radar and DMSP F7 satellite observations in the prenoon sector during a period of Kp > 7, to examine the low-altitude signatures of various plasma regions in the vicinity of the cusp. The combination of particle precipitation, magnetic field perturbation, radar measurements of ion heating, and convection consistently suggests the unusual low-latitude position of cusp at 65 invariant latitude.

• Research Organization: Air Force Geophysics Lab., Hanscom AFB, MA (USA)
• OSTI ID: 6256888
• Report Number(s): AD-A-227081/7/XAB; GL-TR--90-0244
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED-PARTICLE PRECIPITATION
COMPARATIVE EVALUATIONS
CONVECTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY TRANSFER
FLUCTUATIONS
GEOGRAPHICAL VARIATIONS
HEAT TRANSFER
HEATING
INTERPLANETARY MAGNETIC FIELDS
INTERPLANETARY SPACE
ION DRIFT
IONOSPHERE
LATITUDE EFFECT
MAGNETIC FIELDS
MAGNETIC STORMS
MASS TRANSFER
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
PLASMA
POLAR CUSP
RADAR
RANGE FINDERS
SATELLITES
SPACE
VARIATIONS