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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
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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 • Lopéz Fuentes et al, 2006 20 Loops
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)
Synthetic Obs.171 AIA Pixel Size Hi-C Pixel Size 1.0 1.1 1.2 1.3 1.4 1.5 2.0 3.0 4.0 5.0
Synthetic Obs.335 AIA Pixel Size Hi-C Pixel Size 1.0 1.1 1.2 1.3 1.4 1.5 2.0 3.0 4.0 5.0
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?
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