A STUDY OF THE EFFECT AND CONSEQUENCE OF SOLAR-CYCLE VARIATION ON LOW-ENERGY GALACTIC COSMIC-RAYS USING PIONEER-10-H-LYMAN-ALPHA DATA AS A SOLAR-CYCLE PROXY
K. Scherer et al., A STUDY OF THE EFFECT AND CONSEQUENCE OF SOLAR-CYCLE VARIATION ON LOW-ENERGY GALACTIC COSMIC-RAYS USING PIONEER-10-H-LYMAN-ALPHA DATA AS A SOLAR-CYCLE PROXY, J GEO R-S P, 102(A3), 1997, pp. 4653-4659
The correlation of the 1981-1990 (similar to 23 to similar to 50 AU) d
ata of three instruments, the ultraviolet photometer (UV), the charged
particle instrument (CPI), and the trapped radiation detector (TRD),
on board Pioneer 10 is investigated. The reduction. of the data necess
ary for applying a fast Fourier transform (FFT) algorithm is described
. A cross correlation function between the hydrogen Lyman a backscatte
red radiation, used as a solar cycle proxy, and the cosmic ray fluxes
is obtained from the FFT algorithm. The time lag in the anticorrelatio
n function between the galactic cosmic rays and the Lyman alpha line i
s used to determine the distance to the solar wind termination shock (
75 AU), under the assumption that the cosmic ray modulation boundary f
or low-energy particles and the termination shock are coincident. The
ratio of the upwind termination shock distance to the downwind shock d
istance is determined to be 2/3 using the Voyager 1 position in 1996.