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

doi:10.1051/0004-6361:20020581

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

Physics

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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.

Original language	English
Pages (from-to)	295-313
Number of pages	18
Journal	Astronomy and Astrophysics
Volume	389
Issue number	1
DOIs	https://doi.org/10.1051/0004-6361:20020581
Publication status	Published - Jul 2002

Keywords

atomic data
atomic processes
sun
atmosphere
UV radiation
plasma

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10.1051/0004-6361:20020581

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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.",

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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

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DO - 10.1051/0004-6361:20020581

M3 - Article

SN - 0004-6361

VL - 389

SP - 295

EP - 313

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

IS - 1

ER -

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

Abstract

Keywords

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