cross-sectional properties of coronal loops and their implications
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Cross-Sectional Properties of Coronal Loops and Their Implications. Henry “ Trae ” Winter III with Chester Curme. Constant Cross-Section?. Klimchuk et al. 1992 Studied 10 SXT loops Measured an Apex to Footpoint Expansion Factor of. TRACE Loops. Watko & Klimchuk, 2000 22 Loops - PowerPoint PPT PresentationTRANSCRIPT
Cross-Sectional Properties of
Coronal Loops and Their Implications
Henry “Trae” Winter III with
Chester Curme
Constant Cross-Section?
•Klimchuk et al. 1992
•Studied 10 SXT loops
•Measured an Apex to Footpoint Expansion Factor of
TRACE Loops
•Watko & Klimchuk, 2000 22 Loops
•Lopéz Fuentes et al, 2006 20 Loops
DeForest, 2007
DeForest, 2007
Unresolved Structures
Lopés Fuentes et al, 2008
• Countered DeForest’s argument
• Claimed that their method could distinguish between unresolved expanding and not expanding but resolved strands
• Conversation switched to theories that predict constant cross-section loops (i.e. Constant B).
How Could Loops be of Constant Cross-
Section?
•Twist? (Klimchuk et al., 2000)
•Separators? (Plowman et al., 2009)
How Could Loops be of Constant Cross-
Section?
•Emission loops (eLoops) do not actually trace field lines (Peter & Bingert, 2012)
Apex Temperature Evolution
Apex Density Evolution
Over Pressure
Synthetic Obs.171
1.0 1.31.21.1 2.01.51.4 4.03.0 5.0
AIA Pixel Size
Hi-CPixel Size
Synthetic Obs.335
1.0 1.31.21.1 2.01.51.4 4.03.0 5.0
AIA Pixel Size
Hi-CPixel Size
zzzz
Width Measurements
Estimation of Width
AIA171
Estimation of Width
AIA 335
zzzz
Estimation of Width
“Hi-C Like”171
Estimation of Width
“Hi-C Like” 335
Summary• Loop geometry has an effect on fundamental
loop properties such as temperature and density (pressure)
• Vesecky, Antiochos, and Underwood, 1979; Mariska, 1984; Schrijver, Lemen and Mewe, 1989; Dowdy, Emslie, and Moore, 1987
• Modeled near-resolution, expanding loops can appear to be of constant cross-section just like those “pesky” observations
• Loops must be many pixels wide to make width determinations
• Is it safe to use magnetic fields to generate loop geometries for 1D models?
Extra Slides
See Anna Malanushenko’s Work at the SPD
See Anna Malanushenko’s Work
at the SPD
How Could Loops be of Constant Cross-
Section?•Twist? (Klimchuk et al., 2000)
How Could Loops be of Constant Cross-
Section?•Separators? (Plowman et al., 2009)
How Could Loops be of Constant Cross-
Section?•Maybe eLoops do not trace out magnetic
fields? (Peter & Bingert, 2012)
How Could Loops be of Constant Cross-
Section?
Peter &Bingert, 2012
What happens if loops are not of constant cross-
section?
Brooks, et al 2013
Brooks, et al 2013
Brooks, et al 2013