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Prominence-Corona Transition Region. T. Kucera, NASA/GSFC ISSI Prominence Cavity Team Jan. 2009. Outline. Basic structure of the TR What it looks like in the EUV Prominence Motions - Models and Observations ISSI Prominence Group Topics. What is the PCTR?.
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Prominence-Corona Transition Region T. Kucera, NASA/GSFC ISSI Prominence Cavity Team Jan. 2009
Outline • Basic structure of the TR • What it looks like in the EUV • Prominence Motions - Models and Observations • ISSI Prominence Group Topics
What is the PCTR? Material between the bulk of the prominence material at T<104 K and the corona at T>106 K. B
Corona PCTR Prominence PCTR Corona What is the PCTR?
Prominences at 304 Å 304 Å STEREO/SECCHI/EUVI 304 Å SOHO/EIT Contributions: He II collisionally excited (50,000-90,000 K) He II scattered (~104 K) (See Labrosse et al.) Lyman absorption (~104 K) Si XI (~106 K)
Coronal Emission? prominence associated jet TRACE Chae 2003 Not always. These transient bright features at 171 and 195 Å probably around 250,000 K. Erupting prominence, EIT 195 Å Ciaravella et al. 2000
Differential Emission Measures • DEMs assume • Ionization equilibrium • Optically thin plasma Cirigliano et al. 2004 SOHO/SUMER and CDS
Prominence Motions Prominences are dynamic! Quiescent prominences in H show steady flows, including counter-streaming, up to 20 km/s, and sometimes show faster motions. Prominences observed in EUV and UV often show faster motions (30-70 km/s)
Prominence Motions Study prominence motions at different temperatures to understand their properties and how they are related. Goal: to test theories of prominence formation (which tie into theories of magnetic structure).
Rising Magnetic Field Priest, van Ballegooijen, Mackay, 1996
Reconnection driven flows Wang, 1999
Chromospheric Heating/Siphon Flow Models Karpen et al.
Studies of Motions in Prominences - Results Many motions in the EUV seem to be pretty fast Some seem to have detectable H components. Are there EUV components to slower H motions? Its hard to tell, but this may be a resolution problem. In general DEMs of motions look rather like DEMs of prominences of a whole. One difference is the extent to which you can see >300,000 K material in the structure.
Activated Prominence and Cool Loop Apr. 17, 2003 Kucera & Landi 2006
Prominence between active regions Apr. 29, 2004
DEMs of Moving Prominence Features • Different from others Promience DEMs because • Made using as small a piece of a moving feature as possible (in time and space) • When possible “background” has been estimated or subtracted • Calculated with using method of Landi & Landini 1997
Loop Differential Emission Measures Kucera & Landi 2006
Many motions in the EUV seem to be pretty fast Some seem to have detectable H components. Are there EUV components to slower H motions? Its hard to tell, but this may be a resolution problem. In general DEMs of moving features look rather like DEMs of prominences of a whole. One difference is the extent to which you can see >300,000 K material in the structure.
Plans & the Future • Can Dynamic Equilibrium Model simulate the short times scale DEMs? • SDO might be able to help understanding of the “high temperature” TR. Does this have any connection to very high temperature emission associated w/ prominences (“Chewy Nougat”)?
ISSI Prominence Group - Some topics • Prominence Radiative Transfer Observations & Modeling- Lyman Absorption, He lines • PCTR related observations and diagnostics • Flows • Oscillations • Prominence magnetic field, its formations and relationship to the cavity field (Aad)