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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. Ionosonde - Wikipedia

    en.wikipedia.org/wiki/Ionosonde

    These pulses are reflected at various layers of the ionosphere, at heights of 100–400 km (60 to 250 miles), and their echos are received by the receiver and analyzed by the control system. The result is displayed in the form of an ionogram , a graph of reflection height (actually time between transmission and reception of pulse) versus ...

  4. Ionosphere - Wikipedia

    en.wikipedia.org/wiki/Ionosphere

    Relationship of the atmosphere and ionosphere. The ionosphere (/ aɪ ˈ ɒ n ə ˌ s f ɪər /) [1] [2] is the ionized part of the upper atmosphere of Earth, from about 48 km (30 mi) to 965 km (600 mi) above sea level, [3] a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar ...

  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. 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.

  7. Sudden ionospheric disturbance - Wikipedia

    en.wikipedia.org/wiki/Sudden_ionospheric_disturbance

    These fadeouts last for a few minutes to a few hours and are most severe in the equatorial regions where the Sun is most directly overhead. Although High Frequency signals suffer a fadeout because of the enhanced D-layer, the Sudden Ionospheric Disturbance enhances long wave ( VLF ) radio propagation.

  8. Ionospheric Connection Explorer - Wikipedia

    en.wikipedia.org/wiki/Ionospheric_Connection...

    The ionosphere also acts as a conduit for many communications signals, such as radio waves and the signals that make GPS systems work. The ionosphere is where space weather manifests, creating unexpected conditions; electric currents can cause electrical charging of satellites, changing density can affect satellite orbits, and shifting magnetic ...

  9. Radio occultation - Wikipedia

    en.wikipedia.org/wiki/Radio_occultation

    It is used as a weather forecasting tool, and could also be harnessed in monitoring climate change. The technique involves a low-Earth-orbit satellite receiving a signal from a GNSS satellite. The signal has to pass through the atmosphere and gets refracted along the way. The magnitude of the refraction depends on the temperature and water ...