Astron. Astrophys. 362, L21-L24 (2000)

Letter to the Editor

Long-duration cosmic ray modulation from a Sun-Earth L1 orbit

C.D. Pike and R.A. Harrison

Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK

Received 29 June 2000 / Accepted 20 September 2000

Abstract

We analyse cosmic ray hits impacting the detector system of the Coronal Diagnostic Spectrometer aboard the Solar and Heliospheric Observatory spacecraft. These observations allow us to study the modulation of cosmic rays over a 4 year period (1996-2000) running from solar minimum to maximum, from a Sun-Earth L1 Lagrangian orbit. The modulation, at the 45-50% level is consistent with cosmic rays of energy 1 GeV.

Key words: Sun: activity Sun: atmosphere Sun: UV radiation ISM: cosmic rays

Send offprint requests to: C.D. Pike

© European Southern Observatory (ESO) 2000

Online publication: October 24, 2000

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