[Loops] Loop Working group @ Solar Cycle 24 Meeting, Napa

[Robert William Walsh]

Dear Loop-interested colleagues,

This is an invitation to join us in the “Active Region Loop”
Working Group at the meeting
 
 “Solar activity during the onset of Solar Cycle 24” 
8-12 December 2008
The Embassy Suites Hotel in Napa, California
Website: sprg.ssl.berkeley.edu/RHESSI/napa2008/index.php 

With five dedicated workshop sessions, we intend this meeting to be
complementary to the very 
successful “Coronal Loop Meetings” that have held over the last few
years.  

Building upon the wealth of observations from SOHO and TRACE, already
Hinode and STEREO 
are providing new insights and novel views of active region loops that
are both strengthening 
and challenging our current understanding of their fundamental nature.
The torrent of data 
from the up-coming SDO mission will stretch further our current
thinking on their basic make-up, 
how they are heated and their dynamic qualities. Given the above, this
working group will 
address several key science themes associated with active region loops.
These will include 
(but not necessarily restricted to): 

1. Physical properties: At current instrumental resolution, are the
active region loops we 
observe isothermal or multi-thermal? Are they monolithic or
multi-threaded? Will we ever be 
able to distinguish between these two paradigms?  

2. Temporal properties: Is the heat input to loops steady or impulsive?
How can we use the 
techniques of coronal seismology in the Hinode/STEREO/SDO era? 

3. Magnetic properties: Do we now truly have a 3D picture of active
region loop topology? 
How well do current MHD models reproduce the magnetic structure of a
"global" active region? 
On the other hand, how well do these models reproduce the local
magnetic structure within 
an active region?
 
Working on a common dataset:
I would like to pursue the possibility of interested parties working on
a common dataset to 
compare various analysis techniques/approaches. This could be the focus
of one/two sessions.
 
As a first suggestion, I would put forward the dates of 2nd-6th July
2007 based on the 
recent paper that Jane Noglik and I have submitted to Ap J. We have
very much focussed 
on the global aspects of AR10961 but there is much more that could be
examined.

Taken as part of the of the Hinode Observing Programme (HOP) 018, there
are two active 
regions visible on the solar disc with coverage from TRACE (171
Angstroms), STEREO EUVI, 
Hinode XRT and EIS and SOHO synoptic data. Our paper can be found at
 
solar.physics.montana.edu/cgi-bin/eprint/index.pl?entry=7611
 
though please note that it is going through the refereeing process as
we speak!
 
If you have other appropriate datasets that you would like to suggest
for people to look at 
and work on, please email me (rwwalsh at uclan.ac.uk). Once I get
responses back, I can 
put together put a web-based joint list. 
 
Finally, please register for the Napa meeting at
 
sprg.ssl.berkeley.edu/RHESSI/napa2008/abstracts.php
 
as soon as possible. This will not only help with the organization of
this particular working 
group, but will also assist the overall organizers of the meeting in
their preparation activities. 
You don’t necessarily have to pay the registration fee at this stage,
but please indicate which 
working group(s) you will be joining and make your hotel reservations.
 
Thanks and I hope to see you in Napa. Feel free to pass this along to
anyone else who you 
believe would be interested in participating.
 
Robert Walsh, leader – Active Region Loop Working Group
Jeremiah Horrocks Institute for Astrophysics and Supercomputing,
Universityof Central Lancashire,
Preston, Lancashire,
PR1 2 HE
United Kingdom