Three Dimensional Structure and Time Evolution of a Transition Region Explosive Event Observed in He II
Abstract
Transition Region Explosive Events (TREEs) have been observed with slit spectrographs since at least 1975, most commonly in lines of C IV (1548A,1550A) and Si IV (1393A, 1402A). We report what we believe to be the first observation of a TREE in He II 304A. With the MOSES sounding rocket, a novel type of imaging spectrograph, we are able to see the spatial and spectral structure of the event. It consists of a bright core expelling two jets, oppositely directed but not collinear, which curve away from the axis of the core. The jets have both line-of-sight and sky-plane motion. The core is a region of high non-thermal doppler broadening, characteristic of TREEs. It is possible to resolve the core broadening into red and blue line-of-sight components. MOSES captured approximately 150 sec of time evolution before the rocket flight ended. We see the beginning (core activation) and middle (jet ejection), but not the end. It is clear from our data-set that TREEs in He II 304A are much less common than observed in other wavelengths.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- Bibcode:
- 2007AGUFMSH22A0840F
- Keywords:
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- 7526 Magnetic reconnection (2723;
- 7835);
- 7546 Transition region;
- 7549 Ultraviolet emissions;
- 7594 Instruments and techniques