—- at “ wh ewan gy ILLUSTRATIONS 21 Map Showing Location of Stations and Approximate 301 Minimum Frequency Detected at Rongerik for Day of 302 Distances from Bikini . 2. «ec cecccevrsrcecvveees Shot 4, Compared with Normal Values . . . » oe ee 2 Minimum Frequency Detected at Site Elmer for Day of Shot hy Compared with Normal Values . eee es © e@ © © © 33 Highest Frequency of Sporadic-E Reflections at Rongerik Following Shots 1 through 5, Compared Zod Xonospheric Record for 0817 hours on a Normal Day, 305 Ionospheric Records at Rongerik Following Shot 1 by 3.6 Ionospheric Records at Rongerik Following Shot 1 by 59 min to 2 hr 14 min, Showing Unusual Sporadic-E 307 Ionospheric Records at Rongerik Following Shot 2 by 39 min to 2 hr 23 min, Showing Sporadic-E Effects . .. Ionogpheric Records at Rongerix Following Shot 5 by 38 309 with Normal Values . 2. eeccseervrevsvevecse Showing Typical SporadiceE and FeLayer Traces 27 ee 28 34 1/2 to 55 min, Showing Sporadic-E Development .. . 29 and Fl Development eee 30 at Rongerik . ee eee . cece 2.1.0 ec ee eee ee cere cece ene vee 40 min to 2 br 7 min, Showing Unusual Sporadic-E Effects oreeoereeeeeeereeeree ees F2eLayer Virtual Height and Critical Frequency at Rongerik Following Shots J] 1d 2 and at Bikini oe 6 Following Mike Shot (Opera.ion IVY), Compared with Normal Values «2. eeececesecveccevervenr 310 Ionospheric Records at Rongerik Folicwing Shot 1 (left) and Shot 2 (right), Showing Earliest F2 Returns at about 2 1/2 hr after each shot and also F2 Returns from Several Levels about 3 1/4 hr after each shot 3-11 Ionospheric Records at Rongerik Folloring Shot 1 3012 & Posstple Electron-Density Dietribution Above .. (left) and Shot 2 (right) by about 3 1/2 to 4 hr, Showing Stratification of F2 into Two Distinct Layers . Rongerik at Shot 2 Plus 3 hr 49 min, Compared with a Hypothetical Normal Distribution eevee eeveses 3.13 Ionospheric Records at Rongerik Following Shot 1 by 3 br 32 min to 3 hr 50 min, Shcwing Decreasing 301k 23 Virtual Height of the F2 Layer 2. eccce veces Ionospheric Records at Rongerik Following Shot 2 by 3 br 40 min to 4 br, Showing Decreasing Virtual Height of the F2 Layer osoeereeereeve eo verses F2eLayer Virtual Height and Critical Frequency at Rongerik Following Shot 4, Compared with Maximum, Miniman, and Median Normal Values 13 _ SECRET . eoeeeeee ¢ # 8 31