Spectral data obtained by the SO82B experiment aboard SKYLAB were used to critically evaluate existing models of the solar upper photosphere and lower chromosphere. These spectral diagnostics were used to develop new solar models

Heasley, J. N.

English

The use of the solar H I Lyman spectral line as a diagnostic of the lower to middle chromosphere is discussed. Quiet sun Lyman profiles from the photographic spectra were subjected to data reduction and appropriate theoretical modelling was accomplished. Apollo telescope mount data was utilized

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submission. 
 
 
 
 
 
 
 
Produced by the NASA Center for Aerospace Information (CASI) 
https://ntrs.nasa.gov/search.jsp?R=19830003763 2020-03-21T06:48:02+00:00Z
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	 1183-12033UPPER PHOTOSPHERE AND LOWER 4.r' ., i N0SP1iE jE
BASED UPON ATB DATA (Hawa.i.1
	
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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
GEORGE C. MARSHALL SPACE FLIGHT CENTER
FINAL TECHNICAL REPORT
NAS 8-33219 --°
The Modelling of the Solar Upper Photosphere and
Lower Chromosphere Based Upon ATM Data
James N. Heasley
Principal Investigator
Institute for Astronomy
University of Hawaii
2444 Dole Street
Honolulu, Hawaii 96822
Prepared for:
George C. Marshall Space Flight Center
Marshall Space Flight Center
Alabama 35812
2'
THE MODELLING OF THE SOLAR UPPER PHOTOSPHERE AND
LOWER CHROMOSPHERE BASED UPON ATM DATA
Final Technical Report
The scientific objective of this guest investigator program was to use
spectral data obtained by the S082B experiment aboard Skylab to critically
evaluate existing models of the solar upper photosphere and lower chromosphere
and, where possible, to use these spectral diagnostics to develop new solar
models. Research associate Dr. Diane Roussel—Dupre spent the period
12 November to 3 December 1979 at the Naval Research Laboratory in Washington,
D.C. digitizing photographic spectra. This data has served as the basis for
several investigations pertaining to the goals of this research program.
These individual studies are described below.
At the time the original ATM guest investigator proposal was submitted
one problem which was identified was the differences in models of the upper
photosphere and temperature minimum region depending on whether the spectral
diagnostics used in developing the model were continua (see, e.g., Vernazza,
Avrett and Loeser 1976) or spectral lines (see, e.g., Ayres and Linsky 1976
or Heasley and Allen 1979). Heasley et al. 1981 presented new observations
of the Al I autoionization doublet x,1932 and x,1936 and used non—LTE spectrum
synthesis calculations to study the line formation of these features in the
solar atmosphere. The non—LTE effects were found to be important for the line
formation although the results were most sensitive to the "missing opacity" in
the solar ultraviolet. The theoretical profiles for continuum based models
(like the VAL) which have cool temperature minima (T — 4100 K) gave Al I
profiles in good agreement with the ATM spectra while the models with hotter
temperature minima, T — 4500 K (Ayres and Linsky 1976) predicted the Al I
doublet to be somewhat weaker than observed.
3.
ATM observations of the C I multiplets at X1560 and X1657 were reported
by Roussel-Dupre and Heasley (1980).
	
Previous work by Shine et al. (1978)
using full-disk average profiles obtained from OSO-8 showed these lines to be
•	 I
t sensitive to the magnitude of nonthermal broadening present in the lower
P chromosphere.	 The ATM spectra were found to be in reasonable qualitative
^r
agreement with the Shine et al. calculations for the VAL model atmosphere.
These results represent the most complete observations of the C I multiplets
to date, including the profiles in supergranuale cells, chromospheric network,
and the overall center-to-limb behavior of the lines.	 Further theoretical
calculations were attempted at the University of Hawaii Computer Center but
i
proved to be computationally prohibitive due to the complex nature of the
blending problems in the non-LTE calculations.
I
r	 '
The major efforts supported by this guest investigator contract were
I
directed toward using the solar H I Lyman a line as a diagnostic of the lower
to middle chromosphere.	 This work represented a natural extension of
Roussel-Dupre's thesis work at the University of Colorado, and required the
f reduction of the quiet sun Lyman a profiles from the ATM photographic spectra
i and the appropriate theoretical modelling.
	
R
The H I Lyman a line profiles obtained from the Skylab S082B films were
k^
presented by Roussel-Dupre ( 1981, 1982).	 These data represent the most
detailed Lyman a profiles currently available and extend from the line center
to over 6 A into the line wings. 	 Profile variations from center-to-limb, at
different heights above the limb, and over cell and network boundaries were
illustrated.
The Lyman a core exhibits weak or no limb darkening, while the line wings
.'
show weak limb darkening.	 Above the limb the line core has essentially
f
constant integrated intensity and width up to + 12" and may result from
All
r
resonance scattering of chromospheric radiation by coronal neutral hydrogen or
from spicules. On the disk, intensities in the line core appear to correlate
well with the H a network. The Lyman a wing intensities, however, appear to
correlate better with the intensities seen in transition region lines. The
average of profiles acquired over the cell and network region is similar to
profiles obtained in the cell.
Roussel-Dupre (1982b) has recently completed a theoretical investigation
of the Lyman a line formation in the solar chromosphere. Her calculations
include a new form for the redistribution function that includes the effects
of collisional coupling between different energy states. Frequencies in the
Lyman a line wing 0.5 to 6 A from the line center are shown to span the entire
chromosphere in their height of formations. The line wing's usefulness as a
diagnostic probe is limited by a large thermalization length, a result of
almost coherent scattering outside of the doppler core.
Comparing Lyman a calculations for the Vernazza, Avrett and Loeser (1981)
solar models, which were developed largely on the measurements from the Skylab
S055 experiment, with the Lyman a profiles obtained under this guest
investigator contract, Roussel-Dupre finds good agreement in integrated core
intensities, in the line wing shape, and the normalized center-to-limb
behavior. The absolute wing intensities calculated for these models, however,
are a factor of 4 too small. In addition, there is no justification from the
multilevel analysis to decrease the amount of coherent scattering in the wings
to the value y = 0.98 suggested by Vernazza, Avrett and Loeser (1981).
i
Roussel-Dupre makes several suggestions for future calculations which
might improve the agreement between the observed and computed profiles. She
believes that the strong collisional correlation correction terms to the
redistribution function, which have been estimated to be small and hence
Lim au., z 	  _ A
deleted from the current formulations, may be important. Including one
estimate of these terms resulted in a 40% increase in the computed line wing
intensities.
REFERENCES
Ayres, T. R. and Linsky, J. L. 1976, Ap.J. 205, 874.
Heasley, J. N. and Allen, M. S. 1979, Ap.J. 237, 255.
Heasley, J. N., Roussel-Dupre, D., McAllister, H. C. and Beerman, C. 1981,
Ap.J. 248, 352.
Roussel-Dupre, D. 1981, B.A.A.S. 13, 555.
1982a, Ap.J. 256, 284.
1982b, Ap.J. submitted.
Roussel-Dupre, D. and Heasley, J. N. 1980, B.A.A.S. 12, 526.
Shine, R. A., Lites, B. W. and Chipman, E. G. 1978, Ap.J. 224, 247.
Vernazza, J. E., Avrett, E. H. and Loeser, R. 1976, Ap.J. Suppl. 30, 1
(VAL).
Vernazza, J. E., Avrett, E. H. and Loeser, R. '1981, Ap.J. Suppl. 45, 635.


The modeling of the solar upper photosphere and lower chromosphere based upon ATM data

General Disclaimer 
One or more of the Following Statements may affect this Document 
 
 This document has been reproduced from the best copy furnished by the 
organizational source. It is being released in the interest of making available as 
much information as possible. 
 
 This document may contain data, which exceeds the sheet parameters. It was 
furnished in this condition by the organizational source and is the best copy 
available. 
 
 This document may contain tone-on-tone or color graphs, charts and/or pictures, 
which have been reproduced in black and white. 
 
 This document is paginated as submitted by the original source. 
 
 Portions of this document are not fully legible due to the historical nature of some 
of the material. However, it is the best reproduction available from the original 
submission. 
 
 
 
 
 
 
 
Produced by the NASA Center for Aerospace Information (CASI) 
https://ntrs.nasa.gov/search.jsp?R=19840003953 2020-03-21T01:41:31+00:00Z
- ! -C<
AOV 1 -q83
RECEIVED
DEPT
FINAL TECHNICAL REPORT
NAS 8 33219
(KUA-C8-170920) TEE 80DELL280 01 THE SOLAR
691tu 980203P RS M LONER C8E080328EDE
SUZO 0908 A24 RASA Ziaal ?*Chaical ltapart
twwaii pair., EOa01418.) 10 p
11C 102111] AO i 	 CSCL 03H 03/92
X84-12021
Oaclas
48523
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
rwRGE C. MARSHALL SPACE FLIGHT CENTER
The Modelling of the Solar Upper Photosphere and
Lower Chromosphere Based Upon ATM Data
Janes N. Beasley
Principal Investigator
Institute for Astronomy
University of Hawaii
2444 Dole Street
Honolulu, Hawaii 96822
Prepared for:
George C. Marshall Space Flight Center
Marshall Space Flight Center
Alabama 35812
THE MODELLING OF THE SOLAR UPPER PHOTOSPHERE AND
LOWER CM MOSPHERE BASED UPON ATM DATA
Final Technical Report
The scientific objective of this guest investigator program was to use
spectral data obtained by the S082B experiment aboard Skylab to critically
evaluate existing models of the solar upper photosphere and lower chromosphere
and, where possible, to use these spectral diagnostics to develop new solar
models. Research associate Dr. Diane Roussel-Dupre spent the period
12 November to 3 December 1979 at the Naval Research Laboratory in Washington,
D.C. digitizing photographic spectra. This data has served as the basis for
several investigations pertaining to the goals of this research program.
These individual studies are described below.
At the time the original ATM guest investigator proposal was submitted
one problem which was identified was the differences in models of the upper
photosphere and temperature minimum region depending on whether the spectral
diagnostics used in developing the model were continua (see, e.g., Vernazza,
Avrett and Loeser 1976) or spectral lines (see, e.g., Ayres and Linsky 1976
or Heasley and Allen 1979). Heasley et al. 1981 presented new observations
of the Al I autoionization doublet 71932 and X1936 and used non-LTE spectrum
synthesis calculations to study the line formation of these features in the
solar atmosphere. The non-LTC effects were found to be important for the line
formation although the results were most sensitive to the "missing opacity" in
the solar ultraviolet. The theoretical profiles for continuum based models
(like the VAL) which have cool temperature minima (T - 4100 K) gave Al I
profiles in good agreement with the ATM spectra while the models with hotter
temperature minima, T - 4500 K (Ayres and Linsky 1976) predicted the Al I
doublet to be somewhat weaker than observed.
.	 3 ,	 .	 `
ATM observations of the C I multiplets at A1560 and X1657 were reported
by Roussel-Dupre and Heasley (1980). Previous work ky Shine at &1. (1978)
using full-disk average profiles obtained from OSO-8 showed these lines to be
sensitive to the magnitude of nonthermal broadening present in the lower
chromosphere. The ATM spectra were found to be in reasonable qualitative
agreement with the Shine at al. calculations for the VAL model atmosphere.
These results represent the most complete observations of the C I multiplets
to date, including the profiles in supergranuale cells, chromospheric network,
and the overall center-to-limb behavior of the lines. Further theoretical
calculations were attempted at the University of Hawaii Computer Center but
proved to be computationally prohibitive due to the complex nature of the
blending problems in the non-LTE calculations.
The major efforts supported by this guest investigator contract were
directed toward using the solar H I Lyman a line as a diagnostic of the lower
to middle chromosphere. This work represented a natural extension of
Roussel-Dupre's thesis work at the University of Colorado, and required the
reduction of the quiet sun Lyman a profiles from the ATM photographic spectra
and the appropriate theoretical modelling.
The A I Lyman a line profiles obtained from the Skylab S082B films were
presented by Roussel-Dupre (1981, 1982). These data represent the most
detailed Lyman a profiles currently available and extend from the line center
to over 6 A into the line wings. Profile variations from center-to-limb, at
different heights above the limb, and over cell and network boundaries were
Illustrated.
The Lyman a core exhibits weak or no limb darkening, while the line wings
show weak limb darkening. Above the limb the line core has essentially
constant integrated intensity and width up to + 12" and .may result from
resonance scattering of chromospheric radiation by coronal neutral hydrogen or
from spicules. On the disk, intensities in the line core appear to correlate
well with the H a network. The Lyman a wing intensities, however, appear to
correlate better with the intensities seen in transition region lines. The
average of profiles acquired over the cell and network region is similar to
profiles obtained in the cell.
Roussel-Dupre (1982b) has recently completed a theoretical investigation
of the Lyman a line formation in the solar chzomosphere. Her calculations
Include a new fora for the redistribution function that includes the effects
of collisional coupling between different energy states. Frequencies in the
Lyman a line wing 0.5 to 6 A from the line center are shown to span the entire
chromosphere in their height of formations. The line wing's usefulness as a
diagnostic probe is limited by a large thermalization length, a result of
almost coherent scattering outside of the doppler core.
Comparing Lyman a calculations for the Vernazza, Avrett and Loeser (1981)
solar models, which were developed largely on the measurements from the Skylab
S055 experiment, with the Lyman a profiles obtained under this guest
Investigator contract, Roussel-Dupre finds good agreement in integrated core
Intensities, in the line wing shape, and the normalized center-to-limb
behavior. The absolute wing intensities calculated for these models, however,
are a factor of 4 too small. In addition, there is no justification from the
multilevel analysis to decrease the amount of coherent scattering in the wings
to the value y - 0.98 suggested by Vernazza, Avrett and Loeser (1981).
Roussel-Dupre makes several suggestions for future calculations which
might improve the agreement between the observed and computed profiles. She
believes that the strong collisional correlation correction terms to the
redistribution function, which have been estimated to be small and hence
al
sdeleted from the current formulations, may be important. 'Including one
estimate of these terms resulted in a 40% increase in the computed line wing
Intensities.
RZFERENCES
Ayres, T. R. and Linsky, J. L. 1976 9 Ap.J. 205, 874.
Heasley, J. N. and Allen, M. S. 1979, .&.J- 237, 255.
Heasley, J. N., Roussel—Dupre, D., McAllister, He C. and Beeman, C. 1981,
.J. 248 1 352.
Roussel—Dupre, D. 1981, B.A.A.S. 13, 555.
1982a, Ap.J. 256, 284.
1982b, Ap.J. submitted.
Roussel-Dupre, D. and Beasley, J. N. 1980, B.A_A.S. 12, 526.
Shine, R. A., L.ites, Be W. and Chipman, E. G. 1978, Ap.J. 224, 247.
Vernazza, J. E., Anrett, E. He and Loeser, R. 1976, Ap.J. Supple 301 I
(VAL).
Vernazza, J. E., Avrett, E. B. and Loeser, R. 1981, Ap.J. Su 1. 45, 635.


The modelling of the solar upper photosphere and lower chromosphere based upon ATM data

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