SOHO Joint Operations Programme 89
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CDS/TRACE - 18th May 1998
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Coronal Holes
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P.R. Young, R. Esser, H.E. Mason & C.C. Kankelborg

The distinction between plumes and non-plumes in coronal holes
is a crucial one as the solar wind is thought emanate principally
from non-plume areas (cf Dupree et al. 1996, ApJ 467, L12).
Boundary conditions for density and temperature at the base
of the open field lines provide important constraints for
solar wind models, and CDS can provide such information
from the many transition region and coronal lines it observes.
For example there are the density diagnostics: MgVII 319/367
(logT=5.8), MgVIII 317/315 (logT=5.9) and SiIX 349/345, while there
are many lines formed in the temperature region logT=5.8 to 6.2 where
coronal holes are thought to have their maximum temperature.

The co-ordination of CDS with TRACE is required to give detailed
spatial and temporal information on the evolution of coronal hole
areas; in particular how the small coronal bright points seen
in coronal holes (with TRACE in the FeIX/X filter) evolve and
how they interact with the plume and non-plume areas.


CDS
	1) Context raster (LARGE_T/v9, 4' x 4', 40 mins)

	2) Repeats of (COHO22/v20, 2' x 2', 33 mins) in a fixed position.
           The entire raster area should lie within a coronal
           hole and on the solar disk.

Duration: 	6 hours


TRACE

Contact:	Charles Kankelborg

Suggested sequence(s):

	cck.southpolar.1x1.171
	
	- only 171 images, 20 sec cadence, full fov
	
	cck.southpolar.1x1.all
	
	- all lines, 7.5 min cadence, full fov