[Loops] New paper for loops group

[Henry (Trae) Winter]

> 
> 
> Subject:  new paper on loops
> 
> Folks,
> 
>   The following paper has now been accepted by ApJ.  The conclusion
> goes rather against the current consensus:  our observations show that at least some coronal separator surfaces and separators are *darker*
> than the corona around them.  We have no explanation yet.
> 
>   Download the paper from: http://solar.physics.montana.edu/martens/Darkbands_Scott_revisions_20130111.pdf
> 
>   Cheers,
> 
>   Piet Martens
> 
> OUTFLOWS AND DARK BANDS AT ARCADE-LIKE ACTIVE REGION CORE BOUNDARIES
> J. T. Scott, P.C.H. Martens, L. Tarr Dept. of Physics, Montana State
> University Bozeman MT 59717 USA
> 
> ABSTRACT
> Observations from the EUV Imaging Spectrometer (EIS) on board Hinode have revealed outflows and non-thermal line broadening in low intensity regions at the edges of active regions (ARs). We use data from Hinode′s EIS, SDO’s AIA and HMI, and the TRACE instrument to investigate the boundaries of arcade like AR cores for NOAA ARs 11112, 10978, and 9077. A narrow, low intensity region that is observed at the core’s periphery as a dark band shows outflows and increased spectral line broadening. This dark band is found to exist for days and appears between the bright coronal loop structures of different coronal topologies. We find a case where the dark band region is formed between magnetic field from emerging flux and the field of the pre-existing flux. A magnetic field extrapolation indicates this dark band is coincident with the spine lines or magnetic separatricies in the extrapolated field. This occurs over unipolar regions where the brightened coronal field is separated in connectivity and topology. This separation does not appear to be infinitesimal and an initial estimate of the minimum distance of separation is found to be ≈ 1.5-3.5 Mm.
> 
> Subject headings: Solar Corona, Spectral Line Broadening, Coronal Topology, Coronal Loops
> 
> 


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Dr. Henry (Trae) Winter III 		
Astrophysicist				Tel:    617-495-7400
Center for Astrophysics		Fax:   617-496-7577
60 Garden Street, MS 58		Cell:  617-755-7967
Cambridge, MA 02138		hwinter at cfa.harvard.edu
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