Infrared continuum study of the solar atmosphere

The infrared continuum permits direct observation of temperature structure in the solar atmosphere. This gives a straightforward technique for analysis of these structures and their variation with altitude. In conclusion, the solar photosphere seems to present more resistance to compression than should be expected. This unexpected incompressibility cannot be due to an unresolved magnetic field, because its magnitude would have to be of order 4000 Gauss and cause detectable Zeeman broadening. The suppression of the expected limb brightening suggests the existence of irregular granular structure with both horizontal and vertical characteristic sizes of order 1500 km. High-resolution images in the wings of the K-line of ionized calcium show granular structure of this horizontal scale