Observation and analysis of a 3B/X3 solar flare

M. C. LÓPEZ FUENTES; C. H. MANDRINI; M. G. ROVIRA; P. DÉMOULIN

GEOFíSICA INTERNACIONAL

INST GEOPHYSICS UNAM

Año: 2000 vol. 39 p. 65 - 71

0016-7169

We analyze the evolution of active region (AR) NOAA 7070 and relate it to a 3B/X3 solar flare that occured onFebruary 27, 1992. The soft X-ray flare observations were obtained by the SXT (Soft X-ray Telescope) on board theYohkoh satellite, and those in Hα come from the Udaipur Observatory (India). The location of the Hα kernels andribbons, and the shape of soft X-ray loops are compared with the magnetic field model of the AR. Both,observations and model, suggest that the coronal loops are too sheared before the flare and that the configurationrelaxes after energy release. We compute the magnetic free energy using the virial theorem, finding a lower limit of2×10 32 erg; this value is in good agreement with those that are typical for the energy released by solar flares.