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Topic: Radiation zone


  
  Van Allen radiation belt - Wikipedia, the free encyclopedia
The Van Allen radiation belt is a torus of energetic charged particles (i.e.
The presence of a radiation belt had been theorized prior to the Space Age and was confirmed by the Explorer I on January 31, 1958 and Explorer III missions, under Doctor James Van Allen.
Miniaturization and digitization of electronics and logic circuits have made satellites more vulnerable to radiation, as incoming ions may be as large as the circuit's charge.
en.wikipedia.org /wiki/Van_Allen_radiation_belt   (1512 words)

  
 Sun - MSN Encarta
The radiative zone spans from the outer edge of the core, which is 174,000 km (108,000 mi) from the Sun’s center, to 496,000 km (308,000 mi) from the Sun’s center.
Because of this continued ricocheting in the radiative zone, about 170,000 years, on average, are required for a photon of energy to work its way outward from the Sun’s core to the bottom of the convective zone.
At the boundary of the cooler convective zone, the radiative energy has lost too much intensity and the material is too cool and dense to allow the energy to pass through.
encarta.msn.com /encyclopedia_761562112_4/Sun.html   (1502 words)

  
 Structure of the Sun - Wikipedia, the free encyclopedia
In this zone there is no thermal convection; while the material grows cooler as altitude increases, this temperature gradient is slower than the adiabatic lapse rate and hence cannot drive convection.
Convective overshoot is thought to occur at the base of the convection zone, carrying turbulent downflows into the outer layers of the radiative zone.
The thermal columns in the convection zone form an imprint on the surface of the Sun, in the form of the solar granulation and supergranulation.
en.wikipedia.org /wiki/Structure_of_the_Sun   (1629 words)

  
 Device for determining the radiation absorption distribution in a three-dimensional examination zone - United States ...
The radiation sources are line-shaped and are arranged parallel to the axis of rotation and diametrically with respect to the axis of rotation opposite a detector array.
The radiation sources 18a and 18b have the same construction and consist of an electron source 19, deflection coils 20 and a linear anode 21 on which X-radiation is generated by exposure to the electron beam 22.
A uniform distribution of radiation source positions (focus positions) on the cylindrical surface 9 is obtained by superposition of the mechanical movement and the electrical movement of the focus of the X-ray sources 18a and 18b.
xrint.com /patents/us/4309615   (2244 words)

  
 NASA's Cosmos
Radiation and convection are the two ways that energy can travel from one place to another inside a star.
Because of this continuing ricocheting in the radiative zone, it takes about 170,000 years, on average, for radiation to work its way out from the Sun’s core to the bottom of the convection zone.
Their slow motion toward the equator are consistent with measurements of the bands in the photosphere, as well as with the similar drift of the location of sunspots as the 11-year solar cycle of magnetic activity winds down to its minimum and approaches the next maximum.
ase.tufts.edu /cosmos/print_chapter.asp?id=25   (2820 words)

  
 Radiation Zone   (Site not responding. Last check: 2007-11-03)
Consequently, the region surrounding the core of the Sun is known as the radiation zone.
Throughout this region of the solar interior, energy, in the form of radiation, is transferred by its interaction with the surrounding atoms.
In the radiation zone of the Sun the temperature is a little cooler than the core and as a result some atoms are able to remain intact.
solar.physics.montana.edu /YPOP/Spotlight/SunInfo/Radzone.html   (380 words)

  
 Convective Zone   (Site not responding. Last check: 2007-11-03)
Once out of the radiation zone the energy, originally produced in the core, requires a new transport mechanism to continue its journey to the surface.
This new method of transport is required because outside of the radiation zone the temperature is relatively cool, now only 2 million degrees Kelvin as opposed to 5 million in the radiation zone.
The hotter material near the top of the radiation zone (the bottom of the convection zone) rises up and the cooler material sinks to the bottom.
solar.physics.montana.edu /YPOP/Spotlight/SunInfo/Conzone.html   (246 words)

  
 [No title]   (Site not responding. Last check: 2007-11-03)
It is really very simple, and the device we use for measuring radiation levels is called a geiger counter.
So one roentgen is 100,000 times the average radiation of a typical city.
The remains of the reactor were entombed within an enormous steel and concrete sarcophagus, so it is now relatively safe to travel to the area - as long as one do not step off of the roadway and do not stick in a wrong places.......
www.angelfire.com /extreme4/kiddofspeed/chapter1.html   (533 words)

  
 Astronomy/The Sun - Wikibooks, collection of open-content textbooks
Outside the core is a radiative zone, where energy produced in the core travels outward to heat this layer.
Outside the radiation zone and interface region is a convection zone.
This zone sits between the heated radiation zone and the cooler outer layers of the sun.
en.wikibooks.org /wiki/Astronomy/The_Sun   (1184 words)

  
 Radiation "Safe Zone" Migrates With Solar Cycle   (Site not responding. Last check: 2007-11-03)
A "safe zone" in the radiation belts surrounding Earth moves higher in altitude and latitude during peaks in solar activity, according to new research by a NASA-led team.
If the radiation belts were visible, they would resemble a pair of donuts around the Earth, one inside the other with the Earth in the "hole" of the innermost donut.
According to the team, the safe zone is created in a region where conditions are favorable for the VLF waves to kick the particles.
www.ufoinfo.com /space/radiation.shtml   (858 words)

  
 Climate Branch Research
The solar radiation input is the major energy source for the Earth's biosphere, and the direct driving force for atmospheric, and oceanic circulations.
The energy generated in the fusion processes in the inner core is transported though radiative processes in the radiation zone, and by convections in the convection zone to the photosphere, which is what we can see.
Plane-parallel radiation codes are developed for use in calculating radiative effects of clouds, water vapor, and the liquid water drop-size distribution; for the estimation of surface energy balance; and for radiative-convective boundary layer equilibrium calculations.
climate.gsfc.nasa.gov /research/index.php   (986 words)

  
 6(f). The Nature of Radiation   (Site not responding. Last check: 2007-11-03)
Solar radiation spans a spectrum from approximately 0.1 to 4.0 micrometers.
A graph that describes the quantity of radiation that is emitted from a body at particular wavelengths is commonly called a spectrum.
Finally, the amount of radiation passing through a specific area is inversely proportional to the square of the distance of that area from the energy source.
www.physicalgeography.net /fundamentals/6f.html   (802 words)

  
 ACS :: New Radiation Guidelines Safeguard Patients
In some cases, the radiation therapy is used prior to surgery to shrink a tumor — and sometimes after surgery to kill remaining cancer cells.
Radiation is also used in a new procedure to help keep open heart arteries clogged after angioplasty.
However, the most common use of x-rays is in the various diagnostic procedures that most people are familiar with, such as a chest x-ray, computerized tomography or CT scan, and the fluoroscopy used during cardiac catheterization and balloon angioplasty.
www.cancer.org /docroot/NWS/content/update/NWS_1_1xU_New_Radiation_Guidelines_Safeguard_Patients.asp   (777 words)

  
 Radiation from a localized current source
To extract the radiation fields, the distance from the source to observation point is expanded assuming the source is localized and the observation point goes to
However, in many cases, the motion is periodic for a very long time, and it is the energy radiated per cycle or equivalently the power radiated that is desired.
If the motion continues indefinitely, the total energy radiated is infinite, so the mathematics needs to be slightly modified as shown in the spectral resolution notes.
fermi.la.asu.edu /PHY531/radiation   (684 words)

  
 ASTRONOMY: The Sun, the Source of All Our Energy   (Site not responding. Last check: 2007-11-03)
convection zone - the third layer of the sun; the energy is moved in convections with the warmer particles being pushed up and the cooler particles being pushed back towards the radiation zone.
In the radiation zone, the energy produced is radiated out to the next layer.
In the convection zone, energy flows in convection currents, meaning the cooler particles are pushed downward towards the core, while the warmer particles are pushed upwards.
schoolscience.rice.edu /science/curricula/PrintPreviewLearningExperienceOnly.cfm?LEID=2145&CurriculaID=313   (483 words)

  
 Radiation & Fallout | San Francisco Scenario | atomicarchive.com
The initial radiation in the form of gamma rays and neutrons can be a major source of fatalities in the first few miles from a nuclear blast of 1.8 megatons.
The radiation given off by fallout is dangerous because of the way it interacts with the body's cells.
Serious radiation sickness effects as in 100-200 rem and hemorrhage; exposure is a Lethal Dose to 10-35% of the population after 30 days (LD 10-35/30).
www.atomicarchive.com /Example/SF_Example7.shtml   (706 words)

  
 More Solar Radiation is Less
Although, that also expresses of what's existing beyond the Van Allen zone of death is in fact considerably more irradiated, as in mostly solar radiation hot and nasty then we've been told, especially for the likes of L4/L5, and of the moon itself must represent quite a great deal of Sv/y, like perhaps 10e3 Sv/y.
I've been informed that there are methods of cutting the secondary radiation factors, not to mention what a fairly substantial magnetic shield could manage, as long as the energy for sustaining such a field were within budget.
Obviously during solar minimums, the combined galactic background radiation is diminished, though at any time there could be an event worthy of concern if you're situated in a sufficiently high risk location, especially if that's being in a space travel mode with few if any options for avoiding TBI exposure.
guthvenus.tripod.com /space-radiation.htm   (3365 words)

  
 Spaceflight Now | Breaking News | NASA finds lightning clears safe zone in radiation belt
The research may eventually be applied to remove radiation belts around the Earth and other worlds, reducing the hazards of the space environment.
If the Van Allen radiation belts were visible from space, they would resemble a pair of donuts around the Earth, one inside the other, with the planet in the hole of the innermost.
According to the lightning theory, radio waves clear the safe zone by interacting with the radiation belt particles, removing a little of their energy and changing their direction.
www.spaceflightnow.com /news/n0503/08lightning   (1268 words)

  
 Antenna arrays
The field produced in the radiation zone by the end-most antenna is given by (see Eq.
In the direction perpendicular to the array, all elements contribute in phase, and the intensity is proportional to the square of the sum of the individual amplitudes.
A radiation pattern which is narrow in one angular dimension, but broad in the other, is called a fan beam.
farside.ph.utexas.edu /teaching/jk1/lectures/node84.html   (617 words)

  
 NASA - Radiation "Safe Zone" Migrates During Solar Cycle
This process occurs again until the safe zone is clear (represented by a dimming of the red spiral).
Image left: Migration of the radiation-belt safe zone occurs because the optimum wave-particle interaction region responsible for particle losses moves from its solar-minimum location (A) to a corresponding location (B) during solar maximum.
Correspondingly, the safe zone position changes from closer to Earth (shaded blue) during a solar minimum to farther away from Earth (shaded red) during a solar maximum.
www.nasa.gov /centers/goddard/news/topstory/2006/safe_zone_shift.html   (1209 words)

  
 Grimsel Test Site - Radiation Protection - Introduction to Radiation Protection
Radiation protection is ensuring that the use of radionuclide tracers at the GTS does not harm the people who work and visit the GTS and ensures that there is no contamination of the environment.
In 1988, a special area of the GTS tunnels was designated as a radiation controlled zone and this conforms to regulations laid down by HSK regarding the safe handling and use of radionuclides.
The staff working in the controlled zone are monitored for any contamination and all material is handled according to strict regulations.
www.grimsel.com /general/radp_intro.htm   (433 words)

  
 Slide 1   (Site not responding. Last check: 2007-11-03)
The names of the layers are core, photosphere, chromosphere, convection zone, and the radiation zone.
First, the core is the center of the sun and is where  nuclear fusion happens.
  Last, the radiation zone is the next layer out from the core and it gives off radiation.
www.mcps.k12.md.us /schools/rockviewes/Hudson2004_files/slide0008.htm   (112 words)

  
 Star Wars: Databank | Radtroopers
A little-known but highly effective arm of the Empire's stormtrooper divisions, Radiation Zone Assault Troopers are specially equipped to operate in one of the deadliest terrain types.
Though all stormtrooper armor provides some measure of protection against radiation, only the radtrooper suits are proof against extended operations in such environments.
Resistance is often minimal, since the intense radiation is effective, but there are hardy lifeforms in the galaxy immune to such extremes, and they are usually tough opponents requiring seasoned troops.
www.starwars.com /databank/organization/radtroopers/eu.html   (313 words)

  
 Energy Fact File: Radiation Zone   (Site not responding. Last check: 2007-11-03)
Since this bit of the Sun is dominated by radiation it is called the radiative zone.
In the radiative zone, the high energy photons produced by the core interact with the particles there - they are absorbed and emitted many times.
The effect of all these absorptions and re-emissions is to increase the typical wavelength (or, decrease its frequency), from high energy gamma rays (as generated in the core) to visible light at the solar surface.
www.sunblock99.org.uk /sb99/people/JIreland/energy/radzone.html   (327 words)

  
 Belarus Resumes Farming in Chernobyl Radiation Zone - New York Times
The Soviet authorities declared an emergency exclusion zone within 19 miles of the reactor, a circle straddling the border between Ukraine and Belarus.
The zone remains closed, except to the workers overseeing the reactor's decontamination, a few hard-luck pensioners who have drifted back and, increasingly, curious tourists on macabre day trips.
Areas as radioactive as parts of the exclusion zone still appear on maps of Belarus as irregular splashes across the eastern part of the country.
www.nytimes.com /2005/10/22/international/europe/22belarus.html?ei=5088&en=07e23c85fff04159&ex=1287633600&adxnnl=1&partner=rssnyt&emc=rss&adxnnlx=1129987199-jqjznmhyMBGp8oHs7PUXHA   (759 words)

  
 Strahler Companion Ch. 2
As solar radiation flows through the atmosphere, energy is scattered and absorbed by gas molecules and dust particles in the air.
CO2 and water vapor absorb incoming shortwave radiation and outgoing longwave radiation from the earth.
Although net radiation is zero for the earth as a whole, it is positive between latitude 40°N and 40°S and negative poleward of these latitudes.
www.wiley.com /college/strahler/sc/strach2.html   (689 words)

  
 OMEGA ENGINEERING, INC v. RAYTEK corp
Since infrared radiation is not visible to the naked eye, a radiometer user cannot easily determine the size and position of the surface area encompassed by the field of view.
Based on its construction of the claims and the undisputed fact that the accused devices have a laser beam directed to the center of the energy zone, the district court granted summary judgment of noninfringement in Raytek's favor.
When such a [sic] incoherent beam is projected parallel and in close proximity to the outside boundaries of the invisible IR cone, a portion of the incoherent beam would diffuse towards the inside of the energy cone [sic].
www.ll.georgetown.edu /federal/judicial/fed/opinions/01opinions/01-1546.html   (9635 words)

  
 A Simulation Study of Kilometric Radiation ... Auroral Zone Model
These are the total number density as a function of altitude, the choice of electron populations and the velocity-space distribution function for each, and the relative abundance of each component as a function of altitude.
Given the uncertainty in the electron densities and distribution functions measured on the auroral zone field line, these assumptions are probably not unreasonable.
Figure 2 and equation (11) both show that the dominant factor affecting the ionospheric electron density is the exponential decrease due to the parallel electric field.
www-ssc.igpp.ucla.edu /~strange/pands_akr_sim/radiation_2.html   (2267 words)

  
 Thermalphysics.org - NY Times
The underlying physical cause of thermal radiation must not be ignored and this includes the internal structure of matter.
The creation of the radiation zone had resulted in tremendous radiation pressure within the sun.
By invoking a liquid model with a shifted apparent temperature, the radiation zone is no longer required within the sun.
www.thermalphysics.org /nytimes_ad1.html   (3714 words)

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