Interplanetary gas. XXIII. Plasma tail disconnection events in comets: Evidence for magnetic field line reconnection at interplanetary sector boundaries

Attention is focused on a form of cometary activity which has been known for some time but is poorly understood: the discarding of a plasma tail by a comet. We find a link between plasma tail rejections and conditions in the solar wind. A model is presented in which a disconnected tail is the end result of magnetic field line reconnection in the cometary ionosphere caused by the traversal of a magnetic sector boundary. Observations of plasma tails appear to be the best and only method at present of mapping the interplanetary sector structure out of the ecliptic plane