On 21 Apr 2004 06:04:12 -0700, (Hank Nixon)
wrote:

"Mike Koerner" wrote in message news:AZohc.25214$Yf6.24446@fed1read07...
Perhaps NASA will help us with thermal locating. Quoting from a CNN article
currently at http://www.cnn.com/2004/TECH/space/0...vil/index.html
:
Dust particles in a devil become electrified because they rub against one
another. It's like shuffling your feet across the carpet, the researchers
explained. But they figured the positive and negative particles would be
evenly mixed in a dust devil, keeping the overall electrical charge in
balance.

Instead, it turns out smaller particles tend to gain negative charge, and
the wind carries them higher.

Heavier, positive particles remain nearer the surface. The separation of
charges creates a giant battery. And because the particles are in motion, a
magnetic field is generated by the moving electrical charges, the
researchers explained.

They don't yet know for sure what to expect on Mars.

Famous modeler Maynard Hill studied varying electric charge related to
thermals about 25 or 30 years ago. As I recall he found that there was
a horizontal differential related to thermals.
So- he built a device to sense this and steer the model into the
thermal- so cool!
Then he tested it- When turned on it would not turn aircraft into the
thermal and in fact kept the wings absolutely level. Darn!
Why? It turns out that the vertical voltage potential around the
earth is far stronger than the horizontal one due to thermals.
The good news- He invented the electrostatic wing leveler.

Was that before or after he was involved in millimetric radar or LIDAR
at Langley? I don't know which - I don't recall the model magazine
story saying which was being tested.

Anyway, they saw strange woolly blobs and Maynard proved they were
thermals by putting an RC glider up and using two-radio from the radar
room to steer it into the blobs. I believe they discovered that the
radar was seeing dust and insects in the thermal column rather than
density gradients etc.


--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :