Non-equilibrium ionization in the transition region network

✍ Scribed by Michael H. Francis

• Publisher: Springer
• Year: 1981
• Tongue: English
• Weight: 765 KB
• Volume: 69
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00149992

✦ Synopsis

We explore the consequences of the recently reported, persistent downflow of material within the supergranule network. The velocities observed by OSO-8, about 5 km s -1 for C IV A 1548 and 20 km s -1 for O vI h1032, are sufficient to cause the ion distributions to differ significantly from those of ionization equilibrium. Using an accepted temperature model and two models of the velocity fields, we determine the ion distributions of carbon, nitrogen, and oxygen throughout the transition region and compare them with the equilibrium distributions. We then investigate how the temperature model must be modified in order to reconcile the computed line intensities with observed and show that a smaller temperature gradient, and possibly a different pressure distribution, are required. Finally, we demonstrate that the observed downflow is probably adequate to overcome the tendency for thermal diffusion to establish concentration gradients and thus the downflow keeps the atmosphere well mixed.