IMF orientation, solar wind velocity, and Pc 3--4 signals: A joint distribution

Journal Article · Thu Feb 01 04:00:00 UTC 1979 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA084iA02p00527· OSTI ID:6469060

Greenstadt, E W; Singer, H J; Russell, C T; Olson, J V

Separate studies using the same micropulsation data base in the period range 10--150 s have shown earlier that signal levels recorded during September, October, and November 1969 at Calgary correlated positively with both solar wind alignment of the IMF and solar wind speed, but each correlation contained enough scatter to allow for influence of the other factor. In this report, joint correlations of velocity and field direction with parameters representing hourly distributions rather than minima of IMF orientation angle display the relative effect of the two agents on magnetic pulsation signal levels. The joint correlations reduce the overall scatter and show that solar wind speeds above 200--300 km/s and angles between the IMF and the sun-earth line of less than 50/sup 0/--60/sup 0/ are associated with enlarged magnetic pulsation amplitudes. These threshold effects tend to support both the bow shock origin and the Kelvin-Helmholtz amplification of daytime signal transients in the Pc 3, 4 period ranges.

• Research Organization: Space Sciences Department, TRW Defence and Space Systems Group, Redondo Beach, California 90278
• OSTI ID: 6469060
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 84:A2; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640106 -- Astrophysics & Cosmology-- Cosmology
640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CORRELATIONS
DATA
DATA FORMS
EARTH ATMOSPHERE
EXPERIMENTAL DATA
INFORMATION
INTERPLANETARY MAGNETIC FIELDS
ISOLATED VALUES
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MAGNETOSPHERE
NUMERICAL DATA
PULSATIONS
SOLAR ACTIVITY
SOLAR WIND
VELOCITY