Global auroral responses to magnetospheric compressions by shocks in the solar wind: two case studies

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6699794

Craven, J D; Frank, L A; Russell, C T; Smith, E J; Lepping, R P

Two case studies are presented of the global auroral responses to shocks in the solar wind at Earth. The z component of the interplanetary magnetic field, Bz, is negative ahead and behind the first shock and positive for the second case. A sudden-commencement geomagnetic storm develops in each case, with maximum D/sub st/ < or = 190 nT. An immediate auroral response is detected at all longitudes around the auroral oval, in which auroral luminosities increase by a factor of 2 to 3 with the first samples after each sudden commencement. The time delay in obtaining the first sample varies with local time from approx 1 to 18 minutes. No other significant variations in the aurorae are associated with the immediate response. Beginning about 30 minutes after each sudden commencement, the aurorae become active and display significant variations in luminosity and spatial distribution. For B/sub z/ < 0 an intense substorm develops. A sun-aligned transpolar arc forms when B/sub z/ > 0, appearing first at local midnight as a polar arc and then lengthening sunward from the auroral oval across the polar cap to noon at an average speed of about 1 km/sec.

• Research Organization: Iowa Univ., Iowa City (USA). Dept. of Physics and Astronomy
• OSTI ID: 6699794
• Report Number(s): AD-A-175734/3/XAB
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
COMPRESSION
DISTRIBUTION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
INTERPLANETARY SPACE
LUMINOSITY
MAGNETIC FIELDS
MAGNETIC STORMS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SAMPLING
SOLAR ACTIVITY
SOLAR WIND
SPACE
SPATIAL DISTRIBUTION
SUDDEN COMMENCEMENTS