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The role of particle diffusion in the lower transition region: Revised interpretation of emission measuresOur energy-balance models of the lower transit ion region were presented in a previous paper (New Models of the Chromosphere and Transition Region). Here we show the influence of particle diffusion on the calculated hydrogen and helium number densities for a given temperature-density model (model C in the preceding paper). We have also solved the statistical equilibrium and radiative transfer equations for a 13-level He I atom (22 radiative transitions) and a 6-level He II ion (15 radiative transitions) together with He III. The resulting He I and He II level-1 number densities and He III density are shown as functions of temperature. Diffusion substantially increases eta(sub HeI) for T greater than 35,000 K and decreases eta(sub HeI) (while increasing eta(sub(HeII)) between 9,000 and 25,000 K. Including the effects of diffusion also increases eta(sub HeIII) for T less than 60,000 K.
Document ID
19930004288
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Avrett, Eugene H. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Fontenla, Juan M. (Alabama Univ. Huntsville., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1991
Publication Information
Publication: Alabama Univ., Data Evaluation, Analysis, and Scientific Study
Subject Category
Solar Physics
Accession Number
93N13476
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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