Re: Meccanica Quantistica

Inviato da  lalonde il 21/1/2007 11:45:20
Citazione:
semplicemente xchè nemmeno la teoria elettrica dell'universo spiega l'origine dei campi magnetici


Allora vediamo un po:
cito da http://public.lanl.gov/alp/plasma/mag_fields.html :
Citazione:
Plasma, which is rare in our close environment, is the dominating state in the universe as a whole. The Sun and stars as well as the diffuse matter between them and between the galaxies are all in this state, despite their great difference in density and temperature. The only exceptions are the cold celestial bodies such as the Earth and other planets, the satellites, asteroids, comets, meteoroids, and dust grains, all of which account for an extremely small fraction of the know matter in the universe. Furthermore, all the cosmical plasma is magnetized. From the nearest cosmical plasma—the Earth's ionosphere—out to the most distant intergalactic regions all cosmical plasma are penetrated by magnetic fields that influence their physical properties in various, often dramatic, ways.

In diffuse matter, which forms a major part of the universe, the motion of each individual particle is strongly controlled by the magnetic field. For example, a hydrogen ion in the solar wind with a thermal velocity of 20 kilometers per second in the interplanetary magnetic field of 5 nanotesla experiences a magnetic force of that is about 10^7 times stronger than the gravitational force from the Sun. Even in the other extreme, for example, in stellar interiors, where gravitational forces dominate, the magnetic field makes possible wave modes (such as Alfvén waves) that are not possible in nonionized media.

Except in very limited circumstances, all cosmical plasmas carry electric currents that constitute the sources of the magnetic field.


Allora vediamo un po le stelle:
in una nube di plasma incandescente si verifica un pinch che raggruppa la materia utilizzando i campi magnetici fino a quando non prende il sopravvento la gravità e si mette in moto la fornace termonucleare. Da qui le onde magnetoidrodinamiche di Hannes Alvés formano il campo magnatico della stella.

Può filare?....Ricordo che stiamo sempre parlando di plasma

Per approfondire l'argomento plasma cito da Wikipedia dove si parla della sfera di influenza del plasma oltre alla quale le cariche vengono schermate.
Citazione:
Hannes Alfven pointed out that: "In a low density plasma, localized space charge regions may build up large potential drops over distances of the order of some tens of the Debye lengths. Such regions have been called electric double layers. An electric double layer is the simplest space charge distribution that gives a potential drop in the layer and a vanishing electric field on each side of the layer. In the laboratory, double layers have been studied for half a century, but their importance in cosmic plasmas has not been generally recognized.".

Ciao

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