Latitude survey of cosmic-ray intensity by Explorer 7, October 1959 to February 1961

Journal Article · Sun Sep 01 00:00:00 EDT 1963 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/JZ068i017p04885· OSTI ID:4658701

Lin, W. C.; Venkatesan, D.; Van Allen, J. A.

A shielded Geiger tube in the Explorer 7 satellite was used in a comprehensive geographic survey of the intensity of charged particles in the latitude range plus or minus 50.5 deg , in the altitude range 550 to 1100 km, and over the 16-month period October 13, 1959, to February 17, 1951. It was found possible to identify and eliminate contributions by geomagnetically trapped particles and thus to obtain the sum of the absolute intensities of primary galactic cosmic rays and of their charged-particle secondaries (albedo) produced in the atmosphere. Specific results are as follows: (1) The counting-rate data from both northern and southern hemispheres and over a considerable range of longitudes are represented in a simple and coherent manner as a function of a single parameter, the Mcllwain magnetic shell parameter L. (2) The counting rate increases monotonically with increasing L and has an accurately constant value for L> 2.9. (3) The high-latitude knee of the counting rate versus L curve occurs at L = 2.6 (corresponding to the invariant latitude 52 deg ) and is indiscernibly different in the northern and southern hemispheres. (4) The absolute omnidirectional intensity is 0.56 (cm²sec) ^-1 at the equator and 2.0 (cm² sec)/sup -1/ at high latitudes, the ratio being 3.6, (5) At high latitudes the intensity increases by the factor 1.046 plus or minus 0.045 during the 16-month period. (6) In terms of the Quenby-Wenk vertical cutoff rigidity R, in billion volts, the total omnidirectional intensity J/sub o/(> R) = 4.3R/sup -0.83 plus or minus 0.02/ (cm² sec)/sup -1/ for 3 < R < 12bv and J_o= 2.0 (cm² sec-¹ for R < 1.7 bv.

• Research Organization: Iowa State Univ., Iowa City
• Sponsoring Organization: USDOE
• NSA Number: NSA-17-037918
• OSTI ID: 4658701
• Journal Information: Journal of Geophysical Research, Vol. 68, Issue 17; Other Information: Orig. Receipt Date: 31-DEC-63; ISSN 0148-0227
• Publisher: American Geophysical Union
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ATMOSPHERE
BACKGROUND
COSMIC RADIATION
EARTH
EXPLORER SATELLITES
GEIGER-MUELLER COUNTERS
GEOMAGNETIC CUT-OFF RIGIDITY
LATITUDE EFFECT
LEVELS
MAGNETIC FIELDS
MEASURED VALUES
RADIATION BELTS
REFLECTION
SATELLITES
SHIELDING
ZONES