A comparison of Hα and soft X-ray characteristics of spotless and spot group flares

✍ Scribed by V. Ruždjak; B. Vršnak; A. Schroll; R. Brajša

• Book ID: 104642657
• Publisher: Springer
• Year: 1989
• Tongue: English
• Weight: 396 KB
• Volume: 123
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00149108

✦ Synopsis

A comparative analysis of spotless and spot group flares recorded at Hvar and Kanzelh6he Observatories during the 21st cycle of solar activity is presented. The rate of occurrence of two-ribbon flares was found to be significantly higher for the spotless flares. In comparison with spot group flares of corresponding Hot importance, the soft X-ray peak values have been systematically lower for the spotless flares. The highest peak values and the energy released in soft X-rays was found for flares with a He ribbon protruding over a major spot umbra. It was found that the effective plasma temperatures in spotless flares have been considerably lower than the temperatures in spot group flares.