First day of classes. We spent the first part of the period
going over the course information, a
project that you will have to
option of doing, books for the
class, and an outline of topics
that might be covered.
Here are scanned images of the notes on the global electrical circuit.
The global electrical circuit resembles a spherical
capacitor. The two electrodes are the ground and the
ionosphere. THe ground is negatively charged during fair
weather. Positive charge is found not on the second conductor but
distributed in the air between the ground and the ionosphere (most of
the charge is near the ground). Air is a very poor conductor but
does have a finite conductivity. A very weak current flows from
the ionosphere to the ground.
Here are estimates of the fair
weather current density, the toal air-earth current and the resistance
of the air.
It would only take a few minutes to discharge the "spherical
capacitor." This doesn't happen, what keeps the capacitor charged
up?
