Abstract
A UNIQUELY intense pulsation of auroral-associated X rays, followed a solar cosmic flare in September 1966 and was detected by scintillation counters on a balloon platform at an altitude of about 32 km (ref. 1). The X rays were strongly modulated with a period of 4–6 s. Figures 1 and 2 show a portion of the amplitude-modulated intensity, the ratio of intensities in two neighbouring energy channels, the power spectrum for the X-ray intensity ratio, and the spectrum of intensity variations in the lower energy channel. It can be seen that the X-ray spectrum hardens as the pulsations grow and then softens with the subsequent decay, and that there are two peaks in the X-ray power spectrum.
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WICKERSHAM, A. Sound wave modulation of auroral X rays. Nature 249, 538–540 (1974). https://doi.org/10.1038/249538a0
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DOI: https://doi.org/10.1038/249538a0
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