A particular class of active region brightenings seen with the Coronal Diagnostic Spectrometer on SOHO show transition region emission lines enhanced by factors of around 1000 over quiet Sun values. The brightenings have high density ( 1012 cm-3 ) and are estimated to be around 0.1-0.2 arcsec in size. They are predominantly found in active regions whose magnetic structure is rapidly evolving. High cadence time sequences yield lifetimes of around 5 mins.
SOHO 13 Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE
- Pub Date:
- January 2004
- The Sun;
- active regions;