The solar-flare infrared continuum: Observational techniques and upper limits

✍ Scribed by H. S. Hudson

• Publisher: Springer
• Year: 1975
• Tongue: English
• Weight: 456 KB
• Volume: 45
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00152217

✦ Synopsis

Exploratory observations at 20/~ and 350/t have determined detection thresholds for solar flares in these wavelengths. In the 20/1 range solar atmospheric fluctuations (the 'temperature field') set the basic limits on flare detectability at ~ 5 K; at 350/~ the extinction in the Earth's atmosphere provides the basic limitation of ~ 30K. These thresholds are low enough for the successful detection of several infrared-emitting components of large flares. Limited observing time and lack of solar activity have prevented observations of large flares up to the present, but the techniques promise to be extremely useful in the future.

The upper limits obtained thus far, for subflares, indicate that the thickness of the Ha flare region does not exceed ~ 10 km. This result confirms the conclusion of Suemoto and Hiei (1959) regarding the small effective thickness of the Ha-emitting regions in solar flares.