An Alfvén resonator or Ionosphere Alfvén resonator is a spectral
resonance structure
In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or ''forms'', also variously known as ''resonance structures'' or '' ...
found within
geomagnetic fields in the frequency range of 0.1–10
Hz. First reported in 1989, they are ionospheric short-period
geomagnetic variations primarily seen as nighttime phenomena and rarely observed during the day. The nighttime preference is due to lower
electrical conductivity
Electrical resistivity (also called volume resistivity or specific electrical resistance) is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity in ...
in the
ionospheric dynamo region, which enables the
feedback
Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause and effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handle ...
instability
In dynamical systems instability means that some of the outputs or internal states increase with time, without bounds. Not all systems that are not stable are unstable; systems can also be marginally stable or exhibit limit cycle behavior.
...
.
See also
*
Earth–ionosphere waveguide The Earth–ionosphere waveguide is the phenomenon in which certain radio waves can propagate in the space between the ground and the boundary of the ionosphere.
Because the ionosphere contains charged particles, it can behave as a conductor. Th ...
References
Physical chemistry
Ionosphere
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