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			 **   THE GEM MESSENGER   **
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						     Volume 7, Number 25
						     July 2, 1997

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SNOWMASS 97 REPORT
BOUNDARY LAYER CAMPAIGN WG 1:  RECONNECTION ELECTRIC FIELD AND MAGNETOPAUSE
BOUNDARY NORMAL MAGNETIC FIELD
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From: Larry Lyons <larry at atmos.ucla.edu>

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We had an exciting final 2-hour session, and we look forward to
participating in the activities of the new Magnetosphere-Ionosphere
coupling working group.  We found that the following topics to be
particularly deserving of continued study as part of GEM:

1.  Response of convection to IMF changes and to substorms, including the
relative importance of temporal changes over whole polar cap versus
propagation of changes across the cap.

2. Dayside auroral and convection changes in association with substorms.

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          Presentations for Session on Ongoing Work

1.  BAKER:  Convection changes in response to IMF changes and substorms
during May 19-20, 1996 ISTP period.  Steady Bz ~ 0 IMF for 3 hr, followed
by variable IMF.  Noted the uncurling of a very sharply sheared vortex at
15 MLT in association with substorm onset.


3.  GREENWALD:  Observed large flow enhancement coming out of the cusp
following an IMF By change.  Found rapid growth and decay of the
enhancement (~10 min).

3.  RIDLEY:  Ionospheric convection reconfigures in response to large
reorientations of the IMF over a time scale of 8-15 min.  Used data from
120 ground magnetometers incorporated into AMIE.  This is remarkably rapid,
considering that the IMF reconfigurations themselves typically take ~8 min.
(Note by GREENWALD and KLUMPAR:  Initial response can occur in only 3-5 min)

4.  MORETTO:  Dayside high-latitude magnetometer response within <5 min to
sudden impulse event (solar wind density up by factor of 5) on 22 Aug.
1995.  Finds, unexpectedly, no evidence for the formation of traveling
convection vortices.

5.  BLANCHARD:  Dayside separatrix identification with incoherent scatter
radars.  Found that dayside separatrix can be identified to within 0.5
degrees using E-region densities, and reported first measurements of
dayside reconnection using this technique to measure the separatrix.

6.  LU:  Global convection response to 18-19 October magnetic cloud using
AMIE.  Found somewhat longer (~15 min) than others above for convection
response to IMF changes.

7.  SMITH:  Dayside-nightside ground optical comparisons during substorms.
Noted that red-green boundary can provide identification of separatrix.
Found that dayside aurora moves equatorward in response to the substorm
growth phase (a Bz response) and poleward in response to a northward
turning of the IMF that lead to a triggered substorm.


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