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Topic: Ionosphere


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In the News (Sun 16 Jun 19)

  
  NGDC/STP - Introduction to the Ionosphere
The ionosphere is that part of the upper atmosphere where free electrons occur in sufficient density to have an appreciable influence on the propagation of radio frequency electromagnetic waves.
ionospheric structures and peak densities in the ionosphere vary greatly with time (sunspot cycle, seasonally, and diurnally), with geographical location (polar, auroral zones, mid-latitudes, and equatorial regions), and with certain solar-related ionospheric disturbances.
The ionosphere is a dynamic system controlled by many parameters including acoustic motions of the atmosphere, electromagnetic emissions, and variations in the geomagnetic field.
www.ngdc.noaa.gov /stp/IONO/ionointro.html   (312 words)

  
 [No title]   (Site not responding. Last check: )
The ionosphere is the part of the atmosphere that is ionized by solar radiation, and too tenuous to be cooled by contact with other air.
The F layers are responsible for most skywave propagation of radio, and are thickest and most reflective of radio on the side of the Earth facing the sun.
Scientists explore the structure of the ionosphere by bouncing radio waves of different frequencies from it, and using special receivers to detect how the reflected waves have changed from the transmitted waves.
wikiwhat.com /encyclopedia/i/io/ionosphere.html   (150 words)

  
 Ionosphere   (Site not responding. Last check: )
The ionosphere is the part of the atmosphere that is ionized by solar radiation, and too tenuous to be cooled by contact with other air.It forms the inner edge of the magnetosphere and has practical importancebecause it reflects radio waves to distant places on Earth.
The Earth 's ionosphere, though protectedfrom direct solar wind scouring by the magnetosphere (and the Earth'smagnetic field), is a shield of layers that absorbs most energetic wavelengths in the atmosphere.
Lloyd Berkner firstmeasured the height and density of the ionosphere.
www.therfcc.org /ionosphere-24000.html   (1462 words)

  
 Ionosphere
The Earth's ionosphere, though protected from direct solar wind scouring by the magnetosphere (and the Earth's magnetic field), is a shield of layers that absorbs most energetic wavelengths in the atmosphere.
The physics of the ionosphere and outer space plasmas where recombination and collisional excitation (i.e., radiative processes) occur are of interest currently because they are not completely understood: in particular, for the electron.
The ionosphere reflects HF radio waves quite well and is used for medium and long range terrestrial radio communication.
www.xasa.com /wiki/en/wikipedia/i/io/ionosphere.html   (1535 words)

  
 * Ionosphere - (Astronomy): Definition
The ionosphere is one of the highest layer of the Earth's atmosphere.
The ionosphere consists of the D layer, the E layer, and the F layers (q.v.).
Ionosphere The region of the Earth's upper atmosphere containing a small percentage of free electrons and ions produced by photoionization of the constituents of the atmosphere by solar ultraviolet radiation.
en.mimi.hu /astronomy/ionosphere.html   (670 words)

  
 Encyclopedia :: encyclopedia : Ionosphere   (Site not responding. Last check: )
The ionosphere is the part of the atmosphere that is ionized by solar radiation.
When a radio wave reaches the ionosphere, the electric field in the wave forces the electrons in the ionosphere into oscillation at the same frequency as the radio wave.
The space tether uses plasma contactors and the ionosphere as parts of a circuit to extract energy from the Earth's magnetic field by electromagnetic induction.
www.hallencyclopedia.com /Ionosphere   (2716 words)

  
 Ionosphere
The ionosphere is a layer of ionized air in the atmosphere extending from almost 80 km above the Earth's surface altitudes of 600 km and more.
The ionosphere is the region of the atmosphere where the aurorae occur.
Ionisation of air molecules in the ionosphere is produced by ultraviolet radiation from the Sun, and to a lesser extent by high-energy particles from the Sun and from cosmic rays.
www.ace.mmu.ac.uk /eae/Atmosphere/Older/Ionosphere.html   (154 words)

  
 Radio-Electronics.Com :: The Ionosphere
In particular the ionosphere is widely known for affecting signals on the short wave bands where "reflects" signals enabling them to be heard over vast distances, sometimes even at the other side of the globe.
The ionosphere extends over more than one of the meteorological areas, encompassing the mesosphere and the thermosphere, it is an area that is characterised by the existence of positive ions (and more importantly for radio signals free electrons) and it is from the existence of the ions that it gains its name.
The ionisation in the ionosphere is caused mainly by radiation from the Sun.
www.radio-electronics.com /info/propagation/ionosphere/ionosphere.php   (2347 words)

  
 YourArt.com >> Encyclopedia >> Ionosphere   (Site not responding. Last check: )
The F layers are responsible for most skywave propagation of radio waves, and are thickest and most reflective of radio on the side of the Earth facing the sun.
If the transmitted frequency is higher than the plasma frequency of the ionosphere, then the electrons cannot respond fast enough, and they are not able to re-radiate the signal.
Ionograms show the virtual heights and critical frequencies of the ionospheric layers and which are measured by an ionosonde.
www.yourart.com /research/encyclopedia.cgi?subject=/Ionosphere   (2911 words)

  
 What is the Ionosphere?
The ionosphere is a name for the layer of the earth's atmosphere that is ionized by solar radiation.
Because the gas is hot and is in a constant stream of solar energy it becomes a fully ionized plasma.
The ionosphere is composed of three main parts: the D, E, and F regions.
www.uaf.edu /asgp/hex/ionosphere.htm   (647 words)

  
 Ionosphere [Oulu]
Ionospheric electric fields are the main result of the coupling between the magnetosphere and ionosphere.
While at low-latitudes the ionospheric plasma is co-rotating with the Earth, at higher latitudes it is convecting under the influence of the large scale magnetospheric electric field mapped to low altitudes.
The convection pattern leads to ionospheric Hall currents (see E x B drift), and along the auroral oval so-called convection electrojets are formed at about 100 km altitude: eastward electrojet on the duskside, westward on the dawnside.
www.oulu.fi /~spaceweb/textbook/ionosphere.html   (650 words)

  
 Earth Ionosphere Waveguide
The ionosphere and the surface of the Earth form a natural waveguide for VLF signals," explains Bill Taylor, a space scientist at the Goddard Space Flight Center.
The VLF radio signal is ducted to the receiver between the surface of the earth and layers in the ionosphere which reflect radio waves.
In this effort, the effects of decreased solar UV radiation on the ionosphere and thus on the propagation of natural and manmade signals propagating in the Earth-ionosphere waveguide were studied.
electronic.rssg.info /Earth-ionosphere-waveguide.php   (213 words)

  
 The Ionosphere   (Site not responding. Last check: )
This "ionized" region of the atmosphere is a plasma and is referred to as the ionosphere.
Because the ionosphere is not a nice smooth "mirror" the signal can be scattered in many directions causing loss of signal strength and interference from other transmitters.
The ionosphere is particulary disturbed in the auroral regions, and during magnetic sub-storms.
www.ion.le.ac.uk /ionosphere/ionosphere.html   (421 words)

  
 NGDC/STP - Ionospheric Data
The Ionospheric Physics Group of NGDC operates the Ionosphere portion of the World Data Center for Solar-Terrestrial Physics, Boulder, which seeks out and archives data, data products, and information related to the Ionosphere.
Most of the current effort at NGDC is in the Ionospheric Vertical Incidence Sounding discipline.
Ionospheric characteristics can be selected by geographic location, station name or by event and downloaded to our ftp anonymous site or directly to your computer.
www.ngdc.noaa.gov /stp/IONO/ionohome.html   (371 words)

  
 Studying Our Earth And Sun Through The Ionosphere
The ionosphere, the outermost layer in the Earth's atmosphere, is formed when sunlight is absorbed by the Earth's atmosphere on the very edge of space.
Given the vital role of radio communications, an ionospheric observatory was established to monitor the variation in the ionospheric layers to establish their effect on radio reception.
It soon became clear that the strength of the ionospheric layers was controlled by the intensity of extreme ultraviolet and X-ray radiation emitted by the Sun.
www.unisci.com /stories/20011/0118015.htm   (695 words)

  
 The Ionosphere   (Site not responding. Last check: )
The ionosphere is a relatively thin shell around the earth between about 70 and 1000 km above the earth's surface.
As a result of the different electron and ion motions horizontal electrical currents flow in the ionosphere which cause magnetic perturbations on the ground.
The motions can also help generate waves in the ionosphere that move with the electrons and can be detected by radars.
www.nerc-bas.ac.uk /public/uasd/magneto/ionosp/intro.html   (253 words)

  
 PH39010 - IONISED ATMOSPHERE
Active research continues to study ionospheric plasma processes in terms of solar-terrestrial interactions, in particular at high latitudes where the aurorae are a spectacular optical manifestation of incoming particles from space.
Observed behaviours of the mid latitude ionosphere and the equatorial ionosphere.
The High-Latitude Ionosphere and the Magnetosphere: Magnetoscopic regions.
www.aber.ac.uk /modules/current/PH39010.html   (364 words)

  
 ESA - Results from Mars Express and Huygens - Mars Express discovers new layer in Martian ionosphere
Scientists believe its origin may be due to the interaction of the ionosphere with incoming meteorites.
At the same time, the presence of the layer was observed at different times of the day and latitudes — early morning and afternoon in the northern hemisphere of the planet, in the equatorial region and at mid-southern latitudes.
As far as the origin of this layer is concerned, Pätzold and colleagues imagine that a mechanism similar to that occurring in Earth's ionosphere may be in place at Mars.
www.esa.int /SPECIALS/Results_from_Mars_Express_and_Huygens/SEMIAUULWFE_0.html   (620 words)

  
 ISTC - Electronic precursors of earthquakes
Researchers from the Institute of the Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS have observed a chain of interconnected precursors of catastrophic earthquakes in the magnetosphere, geomagnetic field and the Earth’s ionosphere.
They used data from ionosphere observations of the world’s earth-based network of ionosphere stations, which excludes seasonal and daily variations in the state of the ionosphere.
It transpired that 10-15 hours prior to an earthquake there are irregularities that arise in the ionosphere – spikes of electronic density (up to 50% of the norm) of 1 to 3 kilometres in length that move horizontally at a rate comparable to the speed of sound.
www.istc.ru /istc/sc.nsf/news/electronic-precursors-earthquakes.htm   (258 words)

  
 SurfWax: News, Reviews and Articles On Ionosphere
Depending on the cooperation of the ionosphere, the upper layer of the Earth's atmosphere that reflects radio signals, their low-wattage transmitters may reach across the country or across the oceans.
In fair weather, the charge difference between the ionosphere and the ground drives a steady trickle of current from the atmosphere to the ground, despite the fact that air is a...
Sunlight pushes the ionosphere closer to the earth but when the sun sets, the ionosphere moves hundreds of additional miles away from the surface, creating a larger angle when a transmitted radio wave bounces off the ionosphere and returns to earth, giving the radio wave a much greater range.
news.surfwax.com /earthscience/files/Ionosphere.html   (4961 words)

  
 Magnetosphere Ionosphere Atmosphere   (Site not responding. Last check: )
At high latitudes the ionosphere is strongly influenced by particles and electric fields controlled by the magnetosphere.
The high latitude ionosphere is also affected by all these processes as well as by those related to the magnetosphere.
The ionosphere has been studied by radio methods since the early years of this century (and the auroral ionosphere even longer using optical methods).
www.eiscat.uit.no /regions.html   (353 words)

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