Formation of the stable auroral arc that intensifies at substorm onset

Technical Report · Fri Oct 01 04:00:00 EDT 1993

OSTI ID:5410673

Lyons, L R; Samson, J C

In a companion paper, the authors present observational evidence that the stable, growth-phase auroral arc that intensifies at substorm expansion phase onset often forms on magnetic field lines that map to within approximately 1 to 2 R(sub e) of synchronous. The equatorial plasma pressure is 1 to 10 nPa in this region, which can give a cross-tail current greater than 0.1 A/m. In this paper, they propose that the arc is formed by a perpendicular magnetospheric-current divergence that results from a strong dawn-to-dusk directed pressure gradient in the vicinity of magnetic midnight. They estimate that the current divergence is sufficiently strong that a greater than 1 kV field-aligned potential drop is required to maintain ionospheric-current continuity. They suggest that the azimuthal pressure gradient results from proton drifts in the vicinity of synchronous orbit that are directed nearly parallel to the cross-tail electric field.

• Research Organization: Aerospace Corp., El Segundo, CA (United States)
• OSTI ID: 5410673
• Report Number(s): N-94-15433; NASA-CR--193637; NAS--1.26:193637; ATR--92(7248)-2; CNN: NAG5-1541; NSF ATM-90-17637
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
CURRENTS
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTROJETS
MAGNETIC STORMS
ORIGIN
PRESSURE GRADIENTS