Effect of possible passage through Halley's magnetic tail on geomagnetic activity

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA10p11195· OSTI ID:5939925

Russell, C T; Phillips, J L ^[1]; Fedder, J A ^[2]; Allen, J H; Morris, L ^[3]; Craig, R A ^[4]

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1. Univ. of California, Los Angeles (United States)
2. Naval Research Lab., Washington, DC (United States)
3. National Environmental Satellite, Data, and Information Service, Boulder, CO (United States)
4. NASA Ames Research Center, Moffett Field, CA (United States)

The geomagnetic aa index shows that a nonrecurrent magnetic disturbance occurred in May 1910 near the time of the passage of comet Halley through inferior conjunction. Examination of ground-based magnetograms from May 18 to 20, 1910, shows that this disturbance consisted, in part, of a negative bay of the depth expected if the magnetopause currents had ceased. The duration of this bay could have been caused by the Earth's entry into a cometary tail lobe width of about 10{degrees} km. Other features during this period suggest that the Earth may have also earlier grazed the other lobe of the cometary tail and passed through the plasma sheet. If this interpretation is true, the entire region of interaction was about 6 {times} 10{sup 6} km wide 24 {times} 10{sup 6} km downstream from the nucleus. MHD computer simulations of the solar wind interaction with Halley to 7 {times} 10{sup 6} km downstream are consistent with the inferred tail properties. The fact that the signature of the interaction was observed earlier than expected suggests that momentum transfer occurred from the comet to the solar wind over a very extended region of space around the comet. If this momentum transfer deflected the solar wind flow with the 45-km/s transverse velocity of the comet, the observed timing would be consistent with an initially radially flowing solar wind of 750 km/s or a solar wind flow 4{degrees} from the radial of 500 km/s.

• OSTI ID: 5939925
• Journal Information: Journal of Geophysical Research; (United States), Vol. 92:A10; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH PLANET
INTERACTIONS
HALLEY COMET
MAGNETIC STORMS
COMPUTERIZED SIMULATION
DISTURBANCES
GEOMAGNETIC FIELD
MAGNETOPAUSE
MOMENTUM TRANSFER
PLASMA SHEET
SOLAR WIND
COMETS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
MAGNETIC FIELDS
PLANETS
SIMULATION
SOLAR ACTIVITY
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)