A study of opacity in SOHO-SUMER and SOHO-CDS spectral observations - III. The validity of the escape probability model

G.A. Fischbacher, S.D. Loch, H.P. Summers

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The assumptions underpinning escape probability and absorption factor methods for describing spectral emission from optically thick plasmas, are addressed to test the range of validity of the associated expressions and to develop them for use within non-stratified atmospheres which include plasma flow and line blending. It is found that for moderate optical depths ( ~10) the escape probability is an effective tool for accurately describing the effect of opacity on emergent spectral line intensities. Furthermore it is found that the expressions may be used to extract optical depths directly from observational data independently of preconceived atmosphere model ideas. The analysis enables the detection of unresolved spicule-like structures at the solar limb.
LanguageEnglish
Pages295-313
Number of pages18
JournalAstronomy and Astrophysics
Volume389
Issue number1
DOIs
Publication statusPublished - Jul 2002

Fingerprint

opacity
optical thickness
optical depth
escape
spicules
solar limb
plasma
atmospheres
spectral emission
atmosphere
spicule
magnetohydrodynamic flow
line spectra
limb
effect
method
test
detection
analysis

Keywords

  • atomic data
  • atomic processes
  • sun
  • atmosphere
  • UV radiation
  • plasma

Cite this

@article{2569ab6e7813406fbe8bbe56f521e559,
title = "A study of opacity in SOHO-SUMER and SOHO-CDS spectral observations - III. The validity of the escape probability model",
abstract = "The assumptions underpinning escape probability and absorption factor methods for describing spectral emission from optically thick plasmas, are addressed to test the range of validity of the associated expressions and to develop them for use within non-stratified atmospheres which include plasma flow and line blending. It is found that for moderate optical depths ( ~10) the escape probability is an effective tool for accurately describing the effect of opacity on emergent spectral line intensities. Furthermore it is found that the expressions may be used to extract optical depths directly from observational data independently of preconceived atmosphere model ideas. The analysis enables the detection of unresolved spicule-like structures at the solar limb.",
keywords = "atomic data, atomic processes, sun, atmosphere, UV radiation, plasma",
author = "G.A. Fischbacher and S.D. Loch and H.P. Summers",
year = "2002",
month = "7",
doi = "10.1051/0004-6361:20020581",
language = "English",
volume = "389",
pages = "295--313",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
number = "1",

}

A study of opacity in SOHO-SUMER and SOHO-CDS spectral observations - III. The validity of the escape probability model. / Fischbacher, G.A.; Loch, S.D.; Summers, H.P.

In: Astronomy and Astrophysics, Vol. 389, No. 1, 07.2002, p. 295-313.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A study of opacity in SOHO-SUMER and SOHO-CDS spectral observations - III. The validity of the escape probability model

AU - Fischbacher, G.A.

AU - Loch, S.D.

AU - Summers, H.P.

PY - 2002/7

Y1 - 2002/7

N2 - The assumptions underpinning escape probability and absorption factor methods for describing spectral emission from optically thick plasmas, are addressed to test the range of validity of the associated expressions and to develop them for use within non-stratified atmospheres which include plasma flow and line blending. It is found that for moderate optical depths ( ~10) the escape probability is an effective tool for accurately describing the effect of opacity on emergent spectral line intensities. Furthermore it is found that the expressions may be used to extract optical depths directly from observational data independently of preconceived atmosphere model ideas. The analysis enables the detection of unresolved spicule-like structures at the solar limb.

AB - The assumptions underpinning escape probability and absorption factor methods for describing spectral emission from optically thick plasmas, are addressed to test the range of validity of the associated expressions and to develop them for use within non-stratified atmospheres which include plasma flow and line blending. It is found that for moderate optical depths ( ~10) the escape probability is an effective tool for accurately describing the effect of opacity on emergent spectral line intensities. Furthermore it is found that the expressions may be used to extract optical depths directly from observational data independently of preconceived atmosphere model ideas. The analysis enables the detection of unresolved spicule-like structures at the solar limb.

KW - atomic data

KW - atomic processes

KW - sun

KW - atmosphere

KW - UV radiation

KW - plasma

UR - http://dx.doi.org/10.1051/0004-6361:20020581

U2 - 10.1051/0004-6361:20020581

DO - 10.1051/0004-6361:20020581

M3 - Article

VL - 389

SP - 295

EP - 313

JO - Astronomy and Astrophysics

T2 - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

IS - 1

ER -