TABLE: He + (H + ) depletion observations SatelliteDepletion in ions Year, monthRegistration altitudes, km PublicationsF 10.7 Solar cycle OGO-4H+ He+ 21 Sept. 1967 (7 cases) 9,10,18 Feb. 1968 April 1968 700-900 600-800 ~800 Taylor,Grebowsky,Walsh, 19
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