Solar Physics Division Meeting 2000, June 19-22
Session 12. Structure of the Quiet Transition Region
Oral, Chair: E. H. Avrett, Wednesday, June 21, 2000, 10:30am-12:00noon, Forum

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[12.01] Observations: The case for unresolved fine structures

U. Feldman (NRL)

The solar upper atmosphere (SUA) is defined as the volume above the photosphere occupied by plasma with electron temperature above 20,000 K. Until the Skylab era, only little was known about the morphology of the SUA. As a result early models assumed a continuous atmosphere in which the temperature increased with height. With the advances in spectroscopic measurements it became apparent that most of the radiation from the 30,000-500,000 K temperature region could not be explained as coming from a continuous chromosphere-corona interface, but rather from unrelated plasma structures named unresolved fine structures. Recent results obtained by the Extreme Ultraviolet Imaging telescope (EIT), the Solar Ultraviolet Measurements of Emitting Radiation (SUMER) and the Transition Region and Coronal Explorer (TRACE) support the earlier conclusions. An account of observations that were made, over the last three decades, to identify the morphology of the 30,000-500,000 K plasma structures above quiet and coronal hole regions will be given.

This work was supported by the NRL/ONR Solar Magnetism and the Earth's Environment 6.1 Research Option.


The author(s) of this abstract have provided an email address for comments about the abstract: ufeldman@ssd5.nrl.navy.mil

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