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The motivation of this a posting came from a popular article telling about the theory of Earle Williams and colleagues explaining so called D-region ledge below 80 km. The mystery is that are no free electrons in lower atmosphere: one application is to radio communications. Radio waves propagate in ionosphere like in wave guide but not in lower atmosphere which is insulator.
I decided to look whether TGD inspired new physics might tell something interesting about the problem but the conclusion was negative. This search process ended as I realized that the model of Williams and colleagues might elegantly explain also two other poorly understood phenomena related to Earth's atmosphere.
Even worse, a simple estimate using the value of electric field and estimate for ionic conductivity shows that it should take only a time of about 500 seconds for this negative charge to be lost by positive ionic currents from ionosphere (see this)! How Earth can preserve its negative charge? What mechanism prevents these currents from flowing or compensates them with opposite currents? Thunderstorms and electric clouds have been proposed as mechanisms bringing negative charge to Earth. But this only shifts the problem to that of understanding how electric clouds and thunder are generated.
The model explaining D-region ledge could solve also this problem. There would be an ohmic positive ion current to earth and small ohmic electron current upwards in Earth's electric field. But besides this there would be downwards “gravitational” current of negatively charged dust particles compensating the ohmic current in equilibrium! Electrons could drift upwards to D-region from ground but could travel down as free travellers of dust particles!
In purely plasma physical mood one would neglect gravitation altogether since the ratio mg/qE of gravitational and electric forces would be about 10-12 for electron. For dust particles with low enough ratio Q/m ratio one cannot neglect gravitation! Note that dust particles with critical Q/m ratio for which electric and gravitational forces compensate each other could remain stationary in atmosphere. The critical radio would be of order 10-9. From this one can estimate the critical charge of say water droplet, bacterium, or levitating meditator;-).
The model of D-region ledge suggests also a mechanism for the generation of thunder clouds. The electrically charged dust stucks cloud to like dust to water or ice so that the cloud becomes electrically charged. Since the dust does not reach ground and positive ionic current reaches it, the local electric field of Earth changes sign and eventually reaches the value needed for di-electric breakdown.