An extensive data base consisting of VLF records for 130 different propagation paths over a 2-year period was analyzed statistically to study the correlation of VLF propagation changes with solar X-ray events recorded by satellites. Results of the study indicate that with reasonable restrictions on path illumination conditions, it is possible to detect and classify solar X-ray flares, in near realtime, by proper interpretation of VLF phase and amplitude variations. A method of calibrating VLF paths for this purpose is discussed, and a possible global network of receiving stations capable of 24-hr per day monitoring of solar X-rays is described.

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