Electric field observations of equatorial bubbles

Journal Article · Sat Feb 29 23:00:00 EST 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02356· OSTI ID:5398288

Aggson, T L ^[1]; Maynard, N C ^[2]; Hanson, W B ^[3]; Saba, J L ^[4]

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1. NASA Goddard Space Flight Center, Greenbelt, MD (United States)
2. Air Force Geophysics Lab., Hanscom AFB, MA (United States)
3. Univ. of Texas, Dallas (United States)
4. ST Systems Corp., Lanham, MD (United States)

The authors present here results from the double floating probe experiment carried on the San Marco D satellite, with emphasis on the observations of large incremental changes in the convective electric field vector at the boundary of equatorial plasma bubbles. This study concentrates on isolated bubble structures in the upper ionospheric F region and divides these observed bubble encounters into two types, type 1 (live bubbles) and type 2(dead bubbles). Type 1 bubbles show varying degrees of plasma density depletion and upward velocities ranging from 100 to 1,000 m/s. Type 2 bubbles show plasma density depletion but no appreciable upward convection. Both types of events are often surrounded by a halo of plasma turbulence extending considerably outside the region's plasma depletion. Most type 1 events show some evidence for local continuity in the eastward (y) electric current, where the y component of the observed electric field (E{sub y}) shows hyperbolic correlation with the plasma density (n), as dictated by horizontal current continuity. This model stresses the importance of including magnetic field aligned currents in deriving the electric potential equation from the divergence equation {del} {times} j = 0. All of the type 1 (live) events examined exhibit a striking and systematic lack of conservation of the vertical component (x) of the electric field vector (E{sub x}) on crossing these structures. This lack of conservation of E{sub x} is of the order of 1.5 mV/m from west to east, directly implying that type 1 bubbles are not steady state plasma structures. A straightforward interpretation of this jump phenomenon in E{sub x} leads to the conclusion that the walls of most of the type 1 bubbles are collapsing inward at the rate of some 50 m/s.

• OSTI ID: 5398288
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ASYMMETRY
BUBBLES
CORRELATIONS
CURRENTS
EARTH ATMOSPHERE
ELECTRIC CURRENTS
ELECTRIC FIELDS
F REGION
GEOMAGNETIC EQUATOR
IONOSPHERE
MATHEMATICAL MODELS
PLANETARY IONOSPHERES
PLASMA DENSITY
PLASMA DRIFT
SATELLITES
TURBULENCE