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@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