TELLURIC CURRENT MICROPULSATIONS AT THE AURORAL ZONE.
Final rept. Nov 62-Oct 67,
ALASKA UNIV COLLEGE GEOPHYSICAL INST
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The report presents analysis of individual events and statistical results derived from several years of continuous Pc 1 recording at College, using the telluric current technique. Histograms of occurrence distributions versus K sub p and versus pulse period, together with sonagrams, justify dividing Pc 1 into two main classes. Class 1 activity has pulse periods mainly shorter than 3 sec, is usually structured, has a pronounced mid-day maximum in occurrence, not much seasonal variation in occurrence, and has little occurrence relationship to K sub p except for a tendency to be absent when K sub p is large. Class 2 Pc 1 activity has periods usually longer than 2 sec, is usually unstructured, has a very pronounced afternoon maximum in occurrence at College, a seasonal maximum in summer, and has a positive correlation with K sub p. College sonagrams of Pc 1 events show a great variety of frequency-time forms. Rising frequency periodic structures are most common, but falling frequencies are often seen sometimes superimposed on rising events. At times narrow band necklaces are clearly seen. Long duration structured events were observed with durations up to 18 hours. The long events tended to occur only at times of rather low K sub p. Author
- Atmospheric Physics
- Electricity and Magnetism