VLA, PHOENIX and BATSE Observations of an X1 Flare
TUFTS UNIV MEDFORD MA DEPT OF PHYSICS AND ASTRONOMY
Pagination or Media Count:
We present observations of an XI flare detected simultaneously with the Very Large Array VLA the PHOENIX Digital Radio Spectrometer and the Burst and Transient Source Experiment BATSE aboard the Gamma Ray Observatory GRO. The VLA was used to produce snapshot maps of the impulsive burst emission in the higher corona on timescales of 1.7 seconds at both 20 and 01 cm. Our results indicate electron acceleration several minutes before the onset of the hard X- ray burst detected by BATSE. Comparisons with high spectral and spatial observations by PHOENIX reveal a variety of radio bursts at 20 cm, such as type III bursts, intermediate drift bursts, and quasi-periodic pulsations during different stages of the XI flare. From the drift rates of these radio bursts we derive information on local density scale heights, the speed of radio exciters, and the local magnetic field. Radio emission at 90 cm shows a type IV burst moving outward with a constant velocity of 240 kmsec. The described XI flare is unique iii the sense that it appeared at the east limb N06E88 providing the most accurate information on the vertical structure of different flare tracers visible in radio wavelengths.