Metal ions and isotopes in sporadic E-layers during the Perseid meteor shower

The electron density and positive-ion composition above Wallops Island were measured on August 12, 1976, about 12 hours after the maximum of the Perseid shower. At launch time, 4.5 MHz was recorded for fbEs, corresponding to an electron density of 2.4 x 10 to the 5th power per cu cm. Electron profile and ion composition measurements confirmed the presence of a sporadic E-layer with two maxima at 101.3 and 105.4 km. The electron density was measured with a pair of boom-mounted probes at fixed potential. The positive ion composition above 77 km was measured with a magnetic mass spectrometer employing a liquid He cryopump. Some of the salient results of the (still incomplete) analysis are discussed.