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| Paper: |
X-Ray Jets and Their Radio Signatures at Metric and Centimeter Wavelenths |
| Volume: |
154, Cool Stars, Stellar Systems and the Sun: Tenth Cambridge Workshop |
| Page: |
707 |
| Authors: |
van Driel-Gesztelyi, L.; Willson, R. F.; Kile, J. N.; Raoult, A.; Klein, L.; Mein, N.; Rudawy, P.; Cader, B.; Rompolt, B.; Schmieder, B.; Mein, P.; Malherbe, J. M. |
| Abstract: |
On October 19, 1995 at 10:30 UT and 17:00 UT, two semi-homologous X-ray jets were observed with the Yohkoh/SXT from AR 7912, a region having a reversed polarity group with vortex-like Hα fibril pattern and X-ray loops. The jets appeared over a mixed magnetic polarity region in the vicinity of the leading spot. The first event was also observed with the Nancay radio heliograph at 167, 236, and 327 MHz. Type III activity, indicating the presence of electron beams, superimposed on a noise-storm was clearly visible. Type III activity first appeared at 10:25 UT, coincident with the onset of the X-ray jet, at 164 MHz and 236 MHz close to the storm position, and in the direction of the X-ray jet. At 10:28:40 UT a new group of sources appeared eastward of the former activity, which may correspond to another jet branch along a more easterly path seen in the ohkoh} images. The second X-ray jet event was also observed with the Very Large Array (VLA) at 6.2, 20.7, and 91.6 cm. For this event, VLA snapshot maps at 6.2 and 20.7 cm reveal low-brightness temperature changes in source structure at the site of the X-ray jet during the preburst, impulsive, and decay phases. The VLA 91.6 cm observations also show noise storm emission above the active region but there is no clear temporal correlation between this later X-ray jet and the impulsive decimetric bursts that were observed during this period. Although the X-ray observations show that the two jets had similar temperatures, emission measures, speeds and trajectories they appear to have had dissimilar metric responses to these events. This surprising result may question our understanding of the process of electron beam acceleration in jets. |
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