THE DISCONNECTION AND RIPPLING OF THE ION TAIL OF COMET HALE-BOPP

The observations of the large scale structure of Comet Hale-Bopp made around perihelion at Purple Mountain Observatory lead to the following results: 1) Some disconnection events occurred on Feb. 16, 17 and 18 in 1997.From these images it is concluded that the moving velocity of matter within the ion tail is about 50 km/s and the closing speed of a ray toward the main tail axis is 0.080'/s during the corresponding period of observations. 2) There is a rippling appeared in a beam of ion tail on March 3, 1997. Its phase velocity is about 200 km/s and its amplitude is about 0.2 million km. The width of this ion beam is 0.08 million km. The relevant data are obtained by means of PDSmeasurement.