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Publicado: 23 de enero de 2013
Van Allen belt
By: Freddy Alvarez
School: Anglo Americano
Teacher: Roberto Torres
Subject: Physics
Grade: 9th
Van Allen belt
The Van Allen radiation belt is comprised of two torus-shaped layers of energetic charged particles plasma around the planet Earth, held in place by its magnetic field. The belt extends from an altitude of about 1,000 to 60,000 kilometers above thesurface
The Van Allen radiation belt is a torus of energetic charged particles around Earth, trapped by Earth's magnetic field. The Van Allen belts are closely related to the polar aurora where particles strike the upper atmosphere and fluoresce.
The presence of a radiation belt had been theorized prior to the Space Age and the belt's presence was confirmed and first detected by Geigercounters onboard By the Explorer I on January 31, 1958 and Explorer III missions, under Doctor James Van Allen. During the International Geophysical Year and was substantiated by data from later Explorer satellites.
It is named after its discoverer, James Van Allen and also the term 'Van Allen Belts' refers specifically to the radiation belts surrounding Earth; however, similar radiation beltshave been discovered around other planets. The Sun does not support long-term radiation belts.
The Earth actually has two radiation belts of different origins. The inner ring is called the Van Allen belt after its discoverer James Van Allen of the University of Iowa. The belts pose a hazard to satellites, which must protect their sensitive components with adequate shielding if their orbit spendssignificant time in the radiation belts.
The Outer Van Allen belt
The particle population of the outer belt is varied, containing electrons and various ions. Most of the ions are in the form of energetic protons, but a certain percentage are alpha particles and O+ oxygen ions, similar to those in the ionosphere but much more energetic. This mixture ofions suggests that ring current particles probably come from more than one source The outer belt is larger and more diffused than the inner, surrounded by a low-intensity region known as the ring current.
The Inner Van Allen belt
The inner Van Allen Belt extends from roughly 1.1 to 3.3 Earth radii, and contains high concentrations of energetic protons with energies exceeding 100 MeV, trapped bythe strong (relative to the outer belts) magnetic fields in the region.
It is believed that protons of energies exceeding 50 MeV in the lower belts at lower altitudes are the result of the beta decay of cosmic ray neutrons. The source of lower energy protons is believed to be proton diffusion due to changes in the magnetic field during geomagnetic storms.
The Outer Van Allen belt
TheInner Van Allen belt
The Van Allen belt’s Impact on Space Travel
Solar cells, integrated circuits, and sensors can be damaged by radiation. In 1962, the Van Allen belts were temporarily amplified by a high-altitude nuclear explosion (the Starfish Prime test) and several satellites ceased operation.
Magnetic storms occasionally damage electronic components on spacecraft. Miniaturization anddigitization of electronics and logic circuits have made satellites more vulnerable to radiation, as incoming ions may be as large as the circuit's charge. Electronics on satellites must be hardened against radiation to operate reliably.
In practice, Apollo astronauts who travelled to the moon spent very little time in the belts and received a harmless dose.
Nevertheless NASA deliberately timedApollo launches, and used lunar transfer orbits that only skirted the edge of the belt over the equator to minimize the radiation. Astronauts who visited the moon probably have a slightly higher risk of cancer during their lifetimes, but still remain unlikely to become ill because of it.
The Van Allen belt’s And Why They Exist
It is generally understood that the Van Allen belts are a result...
By: Freddy Alvarez
School: Anglo Americano
Teacher: Roberto Torres
Subject: Physics
Grade: 9th
Van Allen belt
The Van Allen radiation belt is comprised of two torus-shaped layers of energetic charged particles plasma around the planet Earth, held in place by its magnetic field. The belt extends from an altitude of about 1,000 to 60,000 kilometers above thesurface
The Van Allen radiation belt is a torus of energetic charged particles around Earth, trapped by Earth's magnetic field. The Van Allen belts are closely related to the polar aurora where particles strike the upper atmosphere and fluoresce.
The presence of a radiation belt had been theorized prior to the Space Age and the belt's presence was confirmed and first detected by Geigercounters onboard By the Explorer I on January 31, 1958 and Explorer III missions, under Doctor James Van Allen. During the International Geophysical Year and was substantiated by data from later Explorer satellites.
It is named after its discoverer, James Van Allen and also the term 'Van Allen Belts' refers specifically to the radiation belts surrounding Earth; however, similar radiation beltshave been discovered around other planets. The Sun does not support long-term radiation belts.
The Earth actually has two radiation belts of different origins. The inner ring is called the Van Allen belt after its discoverer James Van Allen of the University of Iowa. The belts pose a hazard to satellites, which must protect their sensitive components with adequate shielding if their orbit spendssignificant time in the radiation belts.
The Outer Van Allen belt
The particle population of the outer belt is varied, containing electrons and various ions. Most of the ions are in the form of energetic protons, but a certain percentage are alpha particles and O+ oxygen ions, similar to those in the ionosphere but much more energetic. This mixture ofions suggests that ring current particles probably come from more than one source The outer belt is larger and more diffused than the inner, surrounded by a low-intensity region known as the ring current.
The Inner Van Allen belt
The inner Van Allen Belt extends from roughly 1.1 to 3.3 Earth radii, and contains high concentrations of energetic protons with energies exceeding 100 MeV, trapped bythe strong (relative to the outer belts) magnetic fields in the region.
It is believed that protons of energies exceeding 50 MeV in the lower belts at lower altitudes are the result of the beta decay of cosmic ray neutrons. The source of lower energy protons is believed to be proton diffusion due to changes in the magnetic field during geomagnetic storms.
The Outer Van Allen belt
TheInner Van Allen belt
The Van Allen belt’s Impact on Space Travel
Solar cells, integrated circuits, and sensors can be damaged by radiation. In 1962, the Van Allen belts were temporarily amplified by a high-altitude nuclear explosion (the Starfish Prime test) and several satellites ceased operation.
Magnetic storms occasionally damage electronic components on spacecraft. Miniaturization anddigitization of electronics and logic circuits have made satellites more vulnerable to radiation, as incoming ions may be as large as the circuit's charge. Electronics on satellites must be hardened against radiation to operate reliably.
In practice, Apollo astronauts who travelled to the moon spent very little time in the belts and received a harmless dose.
Nevertheless NASA deliberately timedApollo launches, and used lunar transfer orbits that only skirted the edge of the belt over the equator to minimize the radiation. Astronauts who visited the moon probably have a slightly higher risk of cancer during their lifetimes, but still remain unlikely to become ill because of it.
The Van Allen belt’s And Why They Exist
It is generally understood that the Van Allen belts are a result...
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