Table of Contents
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1. Call for Participation at 2010 GEM Summer Workshop:
   Substorm Expansion Onset: The First 10 Minutes
2. GEM Baseline Model Comparison on Tuesday at 3:30
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                     **   THE GEM MESSENGER   **
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                                                  Volume 20, Number 20
                                                         June 12, 2010
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1. Call for Participation at 2010 GEM Summer Workshop:
   Substorm Expansion Onset: The First 10 Minutes
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From: Vassilis Angelopoulos (Vassilis at ucla.edu)
      Kazuo Shiokawa (Shiokawa at stelab.nagoya-u.ac.jp)
      Andrei Runov (arunov at igpp.ucla.edu)
      Shin Ohtani (Ohtani at jhuapl.edu)

Our focus group, "Substorm Expansion Onset: The First 10 Minutes", 
will have 4 sessions at the upcoming GEM Workshop in Snowmass (June 
20-25, 2010).  They are scheduled on June 24 (Thu) and 25 (Fri).  We 
have four topical areas identified, which are:

1. Onset timing: observations/theory/simulations (Angelopoulos)
2. How do onset signatures propagate to near Earth and to the ground?
(Runov)
3. Ground-space mapping of physical processes before/during/after 
onset (Ohtani)
4. Substorm processes near transition between stretched and dipole 
field lines (Shiokawa)

We would like to invite you to participate, and if you have any 
request or question, please contact the person of the topical area of 
your interest, whose name is in the parentheses for each topic.

The description of our focus group is posted at:
http://aten.igpp.ucla.edu/gemwiki/index.php/FG12._Substorm_Expansion_O
nset:_The_First_10_Minutes

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2. GEM Baseline Model Comparison on Tuesday at 3:30
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From: Aaron Ridley and Masha Kuznetsova

Please join us at the GEM Baseline Model Comparison on Tuesday at 3:30.  
We would like to discuss how well MHD models calculate the 
magnetopause position and currents.  We invite modelers to do this for 
idealized conditions and for some events.  For the idealized 
conditions, we ask modelers to utilize a constant Pedersen conductance 
of 5 mhos, 0 Hall conductance, and no dipole tilt.  The solar wind 
density should be set to 5/cc with a velocity of -400 km/s and 
temperature of 100000K.  The IMF By and Bx should be zero, with Bz 
changing from -5 nT down to -10, -20, -30 and -40 nT suddenly at 
roughly 2 hour intervals.  We will then compare the roughly steady 
magnetopause position between the models, to pressure balance and to 
empirical models.  Further, we invite modelers to present the current 
structure (jy) on the Y=0 plane to compare between the different 
models.

In addition, the simulations that were conducted for the GEM Metrics 
Challenge (August 31, 2001; October 29, 2003; August 31, 2005; 
December 14, 2006; 
http://ccmc.gsfc.nasa.gov/ungrouped/extras/GEM_metrics.php) showed a 
wide variety of results for the magnetopause stand-off distance.  We 
will examine the different model results and compare them to pressure 
balance and empirical models.

We invite people to present magnetopause position data or simulation 
results for any of these types of conditions.  If you have a model of 
the magnetopause position, please come and present it.  If you have a 
global model that has been run for these types of conditions, please 
come and present the results.  Please contact us for more information 
or if you would like to give a formal presentation.


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