Fast acceleration of a CME-related X-ray structure in the low solar corona

• Published in: Geophysical research letters 2002-05, Vol.29 (10), p.41-1-41-4
• Main Authors: Alexander, David, Metcalf, Thomas R., Nitta, Nariaki V.
• Format: Article
• Language: English
• Subjects: Acceleration; Coronal mass ejection; Disturbances; Flares; Soft x-rays; Solar corona; Space telescopes; X-rays
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2001GL013670

We report on a unique observation of the early and rapid acceleration of a fast CME in the low solar corona. The coronal disturbance associated with a LASCO CME and concurrent X1.2 flare on 1998 April 23 was well‐observed by the Yohkoh Soft X‐ray Telescope. The X‐ray observations clearly show an accelerating structure, reaching 800–1100 km/s in ∼500s at a de‐projected height of only 280 Mm, indicating an acceleration well in excess of 1700 m/s2. The soft X‐ray observations are coincident with the onset of the CME, which ultimately attained a velocity of 1390 km/s and generated a number of interplanetary radio signatures, frequently associated with fast events. Assuming a constant acceleration, a0, throughout the duration of the X‐ray observations, we determine a best‐fit value of a0 = 1756 m/s2, while application of a power‐law acceleration model yields a better fit to the data with a peak acceleration of ∼4865 m/s2 within the first 280 Mm of the solar corona.