The Structure of the Chromosphere-Corona Transition Region from Limb and Disk Intensities

• Published in: Philosophical transactions of the Royal Society of London. Series A: Mathematical and physical sciences Vol. 270; no. 1202; pp. 81 - 98
• Main Authors: Burton, W. M., Jordan, Carole, Ridgeley, A., Wilson, R.
• Format: Journal Article
• Language: English
• Published: The Royal Society 16-07-1971
• Subjects: Electron pressure; Hydrogen; Ions; Optical thickness; Photometry; Photons; Resonance lines; Solar transition region; Temperature gradients; Wavelengths
• ISSN: 0080-4614
• DOI: 10.1098/rsta.1971.0063

During a rocket flight in April 1969, spectra were obtained of a region of the solar disk and at the solar limb. The absolute disk intensities derived from these data have been used to compute models of the transition region, making the assumptions that the relative abundances of different elements remain constant throughout the atmosphere, and that the electron pressure varies according to the equation of hydrostatic equilibrium. The models obtained are characterized by very steep temperature gradients. The relative intensities of emission lines in the disk and limb spectra have enabled the height of the emitting regions to be determined independently of the above assumptions, and independently of atomic data and absolute intensities. A comparison is made of the structure found by the two methods, and within the accuracy of the present data these are consistent. Emission from low temperature (∼ 104K) material is observed from heights up to 104km above the transition region, and this probably originates in spicules.