Abstract Three distinct boundaries are identified from the PICCA cometary ion observations within the innermost part of the coma of comet Halley: (1) the 'cometopause' at a cometocentric distance Rc ≀ 1.5×105 km, characterized by the appearance of water-group ions well above background; (2) the 'cold cometary plasma boundary' at Rc ≀ 3×104 km, characterized by a sudden and simultaneous decrease in the temperatures of all cometary ions, and (3) the 'ionopause' at Rc ≀ 6000 km, characterized by a fast decrease in the intensity of all cometary ions by a factor 3–5. Between the first two boundaries only ions with masses less than 50 amu are present, showing distinct maximum intensities at 18, 32 and 44 amu at the second boundary. Downstream of the second boundary also ions of mass 12, 64, 76, 86 and 100 amu are detected.
Cometary ion observations at and within the cometopause-region of comet Halley
Advances in Space Research ; 5 , 12 ; 221-225
1985-01-01
5 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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