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Latitude dependence of cosmic-ray cutoff-rigidity variations during the initial phase of a geomagnetic storm

Technical Report ·
OSTI ID:5376978
This paper presents a study on the cosmic-ray cutoff-rigidity variations over Europe during the initial phase of the 17/18 December 1971 geomagnetic storm. Cutoff-rigidity changes deduced from neutron-monitor measurements are compared to results obtained by tracing cosmic-ray trajectories in a model of the perturbed geomagnetic field. It is demonstrated that about 1 hour after the storm sudden commencement at 1418 UT on 17 December 1971 the cosmic ray cutoff rigidities over Europe were increased. Due to the dominating effect caused by the magnetopause currents the increases had a significant amplitude of about 0.3 GV at high latitudes whereas at middle and low latitudes they were only of the order of 0.1GV or less.
Research Organization:
Air Force Geophysics Lab., Hanscom AFB, MA (USA)
OSTI ID:
5376978
Report Number(s):
AD-A-188402/2/XAB; AFGL-TR-87-0287
Country of Publication:
United States
Language:
English