Energetics of the 18 May 1994 brightening event

By using YOHKOH soft X-ray images, vector magnetograms and Hα filtergrams, the energetics of the brightening event of May 18, 1994 has been studied. It occurred in a nearly potential magnetic configuration as shown by the comparison between the magnetic extrapolation (linear force free field) and the large scale soft X-ray loops. This event is related to the emergence of a new magnetic flux. The brightening points of Hα and soft X-ray are located at computed separatrices associated with field lines which are tangent to the photosphere. This brightening may be a signature of reconnection taking place between the pre-existing non-potential loops and the new emerging small loops. The magnetic energy provided by reconnection is likely to be stored in the non-potential loops and shearing emerging flux. A phenomenological model is offered.