The K7RA Solar Update

A coronal mass ejection (CME) hit the Earth on September 30, triggering a jump in geomagnetic indices. The planetary A index on October 1 was 31, and the K index jumped to 7, making aurora visible across the northern tier of the United States. The northern latitude college A index was 23 (near Fairbanks, Alaska), about the same as the mid-latitude index — which was 21 — in Fredericksburg, Vir…

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