NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
The Solar Chromosphere/Corona Interface. I. Far-Ultraviolet to Extreme-Ultraviolet Observations and Modeling of Unresolved Coronal FunnelsA coronal funnel model, developed by D. Rabin, was tested against a calibrated spectroheliogram recorded in the 170-1 75 A bandpass. This image was recorded on board a sounding-rocket experiment flown on 1994 November 3, called the Multi-Spectral Solar Telescope Array II (MSSTA II). MSSTA, a joint project of Stanford University, the NASA Marshall Space Flight Center, and the Lawrence Livermore National Laboratory' is an observing platform composed of a set of normal-incidence, multilayer-coated optics designed to obtain narrow-bandpass, high-resolution images (1 sec.- 3 sec.) at selected far-ultraviolet (FUV), extreme-ultraviolet (EUV), and soft X-ray wavelengths (44-1550 A). Using full disk images centered at 1550 A (C IV) and 173 A (Fe IX/X), the funnel model, which is based on coronal back-heating, was tested against the data incorporating observed constraints on global coverage and measured flux. Found was a class of funnel models that could account for the quiescent, globally diffuse and unresolved emission seen in the 171-175 A bandpass, where the funnels are assumed to be rooted in the C IV supergranular network. These models, when incorporated with the CHIANTI spectral code, suggest that this emission is mostly of upper transition region origin and primarily composed of Fe IX plasma. The funnels are found to have constrictions, Gamma approx. 6-20, which is in good agreement with the observations. Further, the fitted models simultaneously satisfy global areal constraints seen in both images; namely,that a global network of funnels must cover approx. 700 - 95% of the total solar surface area seen in the 171-175 A image, and a 5% of the disk area seen in the 1550 A bandpass. These findings support the configuration of the EUV magnetic network as suggested by Reeves et al. and put forth in more detail by Gabriel. Furthermore, the models are in good agreement with differential emission measure estimates made of the transition region by J. C. Raymond & J. G. Doyle for temperatures 250,000 K less than or = T less than or = 650,000 K, based on full-disk observations made on board Skylab.
Document ID
20040084075
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Martinez-Galarce, Dennis S.
(Lockheed Martin Corp. Palo Alto, CA, United States)
Walker, Arthur C., III
(Stanford Univ. Stanford, CA, United States)
Barbee, Troy W., II
(California Univ., Lawrence Livermore Lab. Livermore, CA, United States)
Hoover, Richard B.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Astrophysical Journal
Publisher: American Astronomical Society
Volume: 585
Subject Category
Solar Physics
Funding Number(s)
CONTRACT_GRANT: NSG-5131
CONTRACT_GRANT: NGT-70284
CONTRACT_GRANT: W-7405-Eng-48
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available