Disappearing solar filaments and geomagnetic activity

Abstract

As a sequel to the recent identification of the high-speed stream as the candidate structure in the solar wind at 1 AU that is primarily responsible for the geomagnetic disturbances occasionally noticed after 'disparition brusques' (DBs) of solar filaments (Sastri et al., 1985), it is reported here that the streams, inferred to be recurrent in an earlier study, were consistently preceded by a stream interface, as expected of corotating streams. This observation substantiates the role of corotating streams of coronal hole origin in the apparent link between DBs and geomagnetic activity, and strengthens the view that DBs are not a unique source of geomagnetic activity.