Optical observations of the AMPTE artificial comet and magnetotail barium releases

The first AMPTE artificial comet was observed with a low light level television camera operated aboard the NASA CV990 flying out of Moffett Field, California. The comet head, neutral cloud, and comet tail were all observed for four minutes with an unifiltered camera. Brief observations at T + 4 minutes through a 4554A Ba(+) filter confirmed the identification of the structures. The ion cloud expanded along with the neutral cloud at a rate of 2.3 km/sec (diameter) until it reached a final diameter of approx. 170 km at approx. T + 90 s. It also drifted with the neutral cloud until approx. 165 s. By T + 190 s it had reached a steady state velocity of 5.4 km/sec southward. A barium release in the magnetotail was observed from the CV990 in California, Eagle, Alaska, and Fairbanks, Alaska. Over a twenty-five minute period, the center of the barium streak drifted southward (approx. 500 m/sec), upward (24 km/sec) and eastward (approx 1 km/sec) in a nonrotating reference frame. An all-sky TV at Eagle showed a single auroral arc in the far North during this period.