Van Allen belt

Development of new applications of radiation modifications of the properties of polymers in high technology industries such as electronics and the exposure of polymer materials to radiation environments as diverse as medical sterilization and the Van Allen belts of space have resulted in a renewed interest in fundamental radiation chemistry of polymers. 

The effects of the radiation flux in space on polymer materials is now of considerable importance due to the increasing use of communications satellites. Geosynchronous orbit corresponds to the second Van Allen belt of radiation, which comprises mainly electrons and protons of high energy. 

Vacuum Vacuum tube Valence Van Allen belts Van der Waals forces Vapor pressure Variable Variable stars Variance... 

A further factor which contributes to the habitable nature of planet Earth is that life on Earth today is protected by the van Allen belt, a product of the Earth s magnetic field. Hence, the dynamo effect of the Earth s core, may also be a significant factor in Earth sustaining life (Nisbet Fowler, 2003). 

Van Allen belts - Two toroidal regions above the earth s atmosphere containing protons and electrons. The outer belt at about 25,000 km above the surface is probably of solar origin. The inner belt at about 3000 km contains more energetic particles from outside the solar system. 

Astronauts would be subject to radiation from gedactic (0,05 rads per day) emd soleU (a few hundred rads per soleU fleU e) cosmic rays as well as leU ge fluxes of low energy radiation when passing through the Van Allen belts (about 0,3 rads per traverse). 

Few of the pions formed in the annihilation process reach the earth s surface. They undergo radioactive decay (life-time about 10 s) to muons and neutrinos, or they collide with other particles in the atmosphere and are annihilated. The muons have properties similar to the electron, but are unstable, decaying with a life-time of about 2 x lO s to electrons and neutrinos. The collision reactions of the pions result in the formation of a large number of other particles such as electrons, neutrons, protons, and photons. Some of the electrons so formed are captured in a thick zone around the earth known as the inner van Allen belt. 

David DeLaney from the University of Tennessee s Physics Department suggested that Infinity World would not have a magnetic field, if the cylinder were hollow. This in turn would have extensive effects on navigation, the Van Allen belts, cosmic radiation, animals navigation, auroras, and so on. 

An important question is what is the probable radiation dose during exposure to the space environment In outer space, unshielded structures may be exposed to as much as 3500 Mrads per day during a solar storm. Organic structures with minimum shielding are exposed to perhaps 10-15 rads per hour. Even at the upper level of 50 rads per hour (Van Allen belt), it would take 2,000,000 hours (229 years) to reach the 100-Mrad dosage level, and mot missions should be completed by that time. ... 

High specific energy to reduce the weight High radiation levels due to Van Allen belt crossing/proximity High reliability... 

The most serious potential noise source is due to charged particle hits on the detectors. Of most concern are trapped particles in the Van Allen belts and the South Atlantic Anomaly. Preliminary calculations show that the problem might be effectively solved however by a combination of screening and careful orbit selection. 

The results mentioned above show that the hostile radiation fields in the inner and outer region of the Van Allen belt in space can be simulated. The radiation doses are no limitations to any space applications of Zerodur . 

Figure 14.10 Cross section of the Van Allen belts encircling the Earth.

Jan.1958 USA. Explorer 1 Tiros 1 First American satellite. Discovery of Van Allen belt. 

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