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  2. High-frequency Active Auroral Research Program - Wikipedia

    en.wikipedia.org/wiki/High-frequency_Active...

    CW transmission is generally used for ionospheric modification, while transmission in short pulses frequently repeated is used as a radar system. Researchers can run experiments that use both modes of transmission, first modifying the ionosphere for a predetermined amount of time, then measuring the decay of modification effects with pulsed ...

  3. Ionosphere - Wikipedia

    en.wikipedia.org/wiki/Ionosphere

    An ionospheric model is a mathematical description of the ionosphere as a function of location, altitude, day of year, phase of the sunspot cycle and geomagnetic activity. Geophysically, the state of the ionospheric plasma may be described by four parameters: electron density, electron and ion temperature and, since several species of ions are ...

  4. Ionospheric storm - Wikipedia

    en.wikipedia.org/wiki/Ionospheric_storm

    The F-region is the highest region of the ionosphere. Consisting of the F1 and F2 layers, its distance above the Earth's surface is approximately 200–500 km. [7] The duration of these storms are around a day and reoccur every approximately 27.3 days. [6] Most ionospheric abnormalities occur in the F2 and E layers of the ionosphere.

  5. Ionospheric heater - Wikipedia

    en.wikipedia.org/wiki/Ionospheric_heater

    This gives an energy density in the ionosphere that is less than 1/100 of the thermal energy density of the ionospheric plasma itself. [1] The power flux may also be compared with the solar flux at the Earth's surface of about 1.5 kW/m 2. During aurora generally no ionospheric effects can be observed with the HF pump facilities as the radio ...

  6. Ionosonde - Wikipedia

    en.wikipedia.org/wiki/Ionosonde

    An example of an ionosonde system displaying an ionogram An ionosonde , or chirpsounder , is a special radar for the examination of the ionosphere . The basic ionosonde technology was invented in 1925 by Gregory Breit and Merle A. Tuve [ 1 ] and further developed in the late 1920s by a number of prominent physicists, including Edward Victor ...

  7. International Reference Ionosphere - Wikipedia

    en.wikipedia.org/wiki/International_Reference...

    It is the international standard empirical model for the terrestrial ionosphere since 1999. For a specified geographic location, time, and date, IRI provides average monthly values for electron density, electron temperature and ion temperature, and the molecular composition of the ions in the range of altitudes from 50 km to 2000 km. [ 1 ] The ...

  8. EISCAT - Wikipedia

    en.wikipedia.org/wiki/EISCAT

    And the VHF radar that operates in the 224 MHz band with transmitter peak power 3 MW, 12.5% duty cycle and 1 μs – 2 ms pulse length with frequency and phase modulation capability. The antenna, used for transmission and reception, is a parabolic cylinder antenna consisting of 4 quarters, constituting a total aperture of 120 m x 40 m.

  9. Space weather - Wikipedia

    en.wikipedia.org/wiki/Space_weather

    Space weather effects. Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere. This includes the effects of the solar wind, especially on the Earth's magnetosphere, ionosphere, thermosphere, and exosphere. [1]