THE DYNAMICAL CHARACTERISTICS OF A DISAPPEARING-FILAMENT ASSOCIATED INTERPLANETARY DISTURBANCE OBSERVED IN 1992 EARLY MAY

The dynamical properties of an interplanetary disturbance related to t he sudden commencement of a geomagnetic storm at 15h41m UT on 1992 May 9 are discussed based on solar-wind data obtained by the interplaneta ry scintillation technique and soft X-ray images taken with the Soft X -ray Telescope on board Yohkoh. It is suggested here that the sudden c ommencement was associated with the disappearance of a quiescent filam ent, which took place in the south-east quadrant of the solar disk at about 07h UT on 1992 May 7. An associated shock wave propagated at app roximately a constant speed of about 1000 km s(-1) up to about 0.3 AU from the Sun, then showed a blast-wave like deceleration. If this was the case, the duration of the ''driven-like phase'' of the shock was a bout 12 hr. According to Yohkoh soft X-ray images, a transient coronal hole was formed near to the disappearing filament. The lifetime of th is coronal hole, about 17 hr, was comparable to the duration of the dr iven phase of the shock wave. A close connection between the dynamical characteristics of the shock wave and the formation of the transient coronal hole is suggested.