High resolution observations of the chromosphere at mm and cm wavelengths
โ Scribed by M. Simon
- Publisher
- Springer
- Year
- 1971
- Tongue
- English
- Weight
- 751 KB
- Volume
- 21
- Category
- Article
- ISSN
- 0038-0938
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โฆ Synopsis
High resolution observations of the Sun at 3.3 ram, 3.5 ram, 1.35 cm, and 1.95 cm which were obtained by tracking narrow beam width antennas on the lunar limb as it occulted the Sun are described. The observations indicate that: (1) the region emitting at these wavelengths is very irregular with typical length scales smaller than one half minute of arc, (2) the number of roughness elements responsible for the irregular structure is small within an area of one half minute of arc square, and (3) the roughness elements observed at wavelengths greater than 1 cm extend to l0 s cm beyond the optical limb.
๐ SIMILAR VOLUMES
lnterferometric observations of the Sun at a wavelength 2 -3.7 cm and an effective angular resolution of 0=7 or 15" are presented. When active regions are observed, circularly polarized radiation is found with an angular size of 0 ~ 15", an effective temperature of T~. 5 โข 105K, and 20 to 303/o circ
Unique long-term visibility variations are detected when the quiet Sun is observed with interferometers operating at 8 mm and 11 cm wavelength with angular resolutions of -0.5'. Quasiperiodic fluctuations in fringe amplitude are observed with periods between 20 and 30 rain, and with amplitude nulls