A model for the transient magnetospheric response to sudden solar wind dynamic pressure variations

Journal Article · Sun Apr 01 04:00:00 EDT 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA04p03755· OSTI ID:5152510

Sibeck, D G ^[1]

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1. Johns Hopkins Univ., Laurel, MD (United States)

Brief, impulsive, large-amplitude ({delta}p/p {approximately} 1{minus}) solar wind dynamic pressure pulses, recurring on time scales of 5 to 15 min, are common just upstream of the Earth's bow shock. When each pulse strikes the magnetopause, it launches a fast-mode compressional wave in the magnetosphere that can propagate antisunward, although sunward motion is common on the early post-noon magnetopause. The greatest amplitude ({approximately} 1 to 2 R{sub E}) magnetopause motion occurs on the prenoon magnetopause, at high-latitudes, and during periods of southward interplanetary magnetic field. The signatures of the pressure-pulse-driven magnetopause motion include a bipolar magnetic field signature normal to the nominal magnetopause, a rotation of the magnetic field away from both magnetosheath and magnetospheric orientations, a mixture of magnetosheath and magnetospheric plasmas, and high-speed magnetosheath plasma flows. The magnetopause boundary motion, in turn, drives transient compressions and shears in the dayside magnetospheric magnetic field. These compressions and shears map to the dayside auroral ionosphere, where the ground signatures produced by a single, brief, solar wind dynamic pressure pulse are an antisunward moving (sunward at early post-noon local times) double-convection vortex, associated with north-south magnetic field perturbations, increased ELF/VLF wave activity, precipitating particles, and cosmic noise absorption. The ionospheric and magnetospheric signatures driven by solar wind pressure pulses greatly resemble those previously associated with flux transfer events.

• OSTI ID: 5152510
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A4; ISSN 0148-0227; ISSN JGREA
• 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
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
FUNCTIONS
INTERACTIONS
INTERPLANETARY MAGNETIC FIELDS
IONOSPHERE
MAGNETIC FIELDS
MAGNETOPAUSE
MAGNETOSHEATH
MATHEMATICAL MODELS
PLANETARY IONOSPHERES
PLASMA DRIFT
PLASMA PRESSURE
RADIATIONS
RESPONSE FUNCTIONS
SHOCK WAVES
SOLAR ACTIVITY
SOLAR WIND
VARIATIONS