The Onset Times of Forbush-Type Cosmic Ray Intensity Decreases

Journal Article · Tue Sep 01 04:00:00 EDT 1959 · Canadian Journal of Physics

DOI:https://doi.org/10.1139/p59-108· OSTI ID:4197715

Fenton, A. G.; McCracken, K. G.; Rose, D. C.; Wilson, B. G.

The onset times of a number of Forbush-type decreases observed at four widely spaced stations are compared, and it is shown that appreciable differences occur. The stations selected were Hobart, Mawson, Ottawa, and Sulphur Monntain. It was found that a consistent pattern is obtained for the events studied when the onset times are plotted as a function of the direction of maximum sensitivity of the recorders relative to the earth-sun line. This is interpreted as being due to a directional anisotropy that exists in the mechanism producing the decreases, at least in the early stages. The depression occurs first for particles arriving from directions between 30 deg and 120 deg aest of the earth- sun line. The relation between these observations and geomagnetic disturbances and the quiet-day daily variation is discussed.

• Research Organization: Univ. of Tasmania, Hobart, Australia; National Research Council, Ottawa
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-000790
• OSTI ID: 4197715
• Journal Information: Canadian Journal of Physics, Journal Name: Canadian Journal of Physics Journal Issue: 9 Vol. 37; ISSN 0008-4204
• Publisher: Canadian Science Publishing
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ANGULAR DISTRIBUTION
ANISOTROPY
COSMIC RADIATION
DISTURBANCES
DIURNAL VARIATION
EARTH
FORBUSH DEPRESSION
MAGNETIC FIELDS
MOTION
PHYSICS
SUN
TURBULENCE
VARIATIONS