Abstract
By using Yohkoh soft X-ray data, Halpha filtergrams, and radio data, the activation of the
disappearing filament and the flare eruption on 7 May 1992 have been studied. Main conclusions
are as follows: (1)the emergence of new magnetic flux tends to affect the pre-existing X-ray
loops, which usually appear in arcades spanning Halpha filament, changing the magnetic
environment of the filament, and then enhance the current in the filament. Therefore newly
emerging flux plays a fundamental role in the destabilization of this filament. (2)According to the
Halpha data and the rising motion of the filament, the corresponding current variation in the
filament has been calculated. It seems that the current interruption may be a possible trigger
mechanism for this filament disappearance. (3)The magnetic field strength and the energy flux of
energetic electrons in the source region of microwave bursts have been estimated by using the
microwave spectrum. During the main phase, the mean magnetic strength and the energy flux of
energetic electrons are about 300-400G and 1x1011ergcm-2s -1, respectively. (4)The energy
provided by reconnection of the current sheet and the total energy of the current filament are
estimated and we show that there is enough energy stored in the filament to feed the 7 May, 1992
flare.