January 18, 2003
Well, another day of no wind...no surface or high altitude
atmospheric winds, so that's good for keeping the rocket
batteries warm and keeping the trajectory nominal, but
no solar wind either, so that's not so good for auroral
activity. The solar wind remains stubbornly pointed
northward (you can see this on the ACE data) so we have
very little energy coming into the near-Earth space
region, and therefore very quiet auroral activity levels.
We are moving into a period of not-so-good (atmospheric)
weather; it's beginning to snow. This makes it difficult
to launch the rocket for several reasons: the clouds
and snow make the auroral cameras blind, so we can't see
what's going on, and, the (atmospheric) winds pull heat
quickly out of the payload and motors and batteries if
we elevate the launch rail up out of the shelter. It takes
us about half an hour to go from horizontal in the shelter,
to ready-to-launch, so if we need to stay protected in
the shelter because of winds, it means we can't jump easily
at a quickly appearing event. We'll see how these conflicting
requirements play out over the next few days. Hopefully
we'll have stronger (solar) wind coupling and stronger
activity levels; this makes the events we are looking
for bigger, and easier to catch with a rocket.
I've attached a snapshot of the convection patterns of
the ionosphere over the polar cap. These flow patterns
(horizontal motions of ions and electrons at a few hundred
km altitude in the lower ionosphere) are what are measured
by some of the radars. The two big D-shaped "lobes" of
convection are caused by the solar wind pulling back on
the Earth's magnetic field lines across the polar cap. High latitude
regions thus flow "antisunward" from noon to midnight, and
then a return convection flow pattern sets up which has
lower latitude areas flowing sunward. You can see Svalbard
as the small triangular island east of Greenland; what
we want is for the split between the two convection lobes
to be near Svalbard (this is where the ion outflow events
occur) and to have strong flows here as well (with strong
flows, the contour lines intensify and steepen up, like
a steep hill on a topo sheet map.) This event shown in
the figure is pretty wimpy looking, because we've had such
lousy coupling to the solar wind (Bz-north as per ACE.)
You can follow these convection patterns on the page
listed on the links section of our "Interactive Page".
These patterns, plus the ACE data, set up the general
conditions for a good event.
We'll hope for lots of solar wind and not much atmospheric
winds (or snow!!...) tomorrow morning.
-K
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