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Los Alamos Scientific Laboratory instrumentation on Imp 7 has detected large fluxes of He + within that volume of solar wind plasma believed to be the solar ejecta driving the interplanetary shock wave disturbance of July 29, 1977. The very high He + /He ++ abundance ratio of 0.3 measured during this event suggests that this was solar prominence material only partially ionized by its passage through the corona.
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Gosling et al. (1980) studied this question.
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