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Relation between Flare-associated X-Ray Ejections and Coronal Mass Ejections.
The Astrophysical Journal
|October 8, 1999
Summary
Researchers identified soft X-ray signatures of coronal mass ejections (CMEs) using Yohkoh SXT data. While X-ray ejections correlate with CMEs, they likely don't represent the CME front itself.
Area of Science:
- Solar Physics
- Astrophysics
- Space Weather
Background:
- Coronal Mass Ejections (CMEs) are significant solar phenomena impacting space weather.
- Directly observing CME signatures in soft X-ray wavelengths is crucial for understanding their initiation and evolution.
- Previous studies have explored correlations between solar flares and CMEs.
Purpose of the Study:
- To identify direct soft X-ray signatures of coronal mass ejections (CMEs).
- To compare Yohkoh soft X-ray telescope (SXT) observations with Solar and Heliospheric Observatory (SOHO) LASCO data for 17 limb flares.
- To investigate the relationship between X-ray ejections and CME onset times and properties.
Main Methods:
- Analyzed Yohkoh SXT images for plasma ejections associated with 17 limb flares.
- Compared SXT observations with contemporaneous data from the SOHO LASCO instrument.
- Examined height-time relationships to estimate CME onset times relative to X-ray ejections.
Main Results:
- A general correlation was found between the presence of X-ray ejections and CMEs.
- X-ray ejections likely do not represent the CME front due to CME acceleration dynamics.
- Estimated CME onset times sometimes preceded the associated flare's impulsive phase.
Conclusions:
- The occurrence of flare-associated plasma ejections in X-rays may depend on open magnetic field lines, potentially created by preceding CMEs.
- Soft X-ray observations provide valuable, though indirect, signatures of CME activity.
- A rare observation of a CME's three-part structure preceding a major flare was presented.