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Initial observations of the artificial stimulation of ULF pulsations by pulsed VLF transmissions

1975; American Geophysical Union; Volume: 2; Issue: 4 Linguagem: Inglês

10.1029/gl002i004p00146

1944-8007

A. C. Fraser‐Smith, C. A. Cole,

Geophysics and Sensor Technology

Initial results are presented from an experiment to generate artificial ultra‐low‐frequency (ULF) hydromagnetic waves in the magnetosphere and ionosphere by means of specially modulated very‐low‐frequency (VLF) transmissions into the magnetosphere. The data were obtained predominantly during the interval September 1–7, 1973, when frequency‐shift‐keyed (FSK) VLF transmissions were made from Siple Station, Antarctica, and simultaneous VLF and ULF recordings were made at the conjugate point (Roberval, Quebec). The same 8‐hour transmission schedule was followed each day; it consisted primarily of intervals of FSK transmission (pulse lengths in the range 200 msec to 3.2 sec) interspersed with intervals of no transmission. All ULF pulsations with frequencies in the Pc 1 range (0.2 to 5 Hz) that occurred during the experiment started in an interval of FSK transmission and the average rate of occurrence of the ULF activity was about twice the rate observed on days with no transmissions.