Editing Ionosphere (section)

==Persistent anomalies to the idealized model==
{{Unreferenced section|date=July 2024}}
[[File:Ionosphere-Thermosphere Processes.jpg|thumb|Overview of ionosphere phenomena]]
[[Ionogram]]s allow deducing, via computation, the true shape of the different layers. Nonhomogeneous structure of the [[electron]]/[[ion]]-[[Plasma (physics)|plasma]] produces rough echo traces, seen predominantly at night and at higher latitudes, and during disturbed conditions.

===Winter anomaly===
At mid-latitudes, the F<sub>2</sub> layer daytime ion production is higher in the summer, as expected, since the Sun shines more directly on the Earth. However, there are seasonal changes in the molecular-to-atomic ratio of the neutral atmosphere that cause the summer ion loss rate to be even higher. The result is that the increase in the summertime loss overwhelms the increase in summertime production, and total F<sub>2</sub> ionization is actually lower in the local summer months. This effect is known as the winter anomaly. The anomaly is always present in the northern hemisphere, but is usually absent in the southern hemisphere during periods of low solar activity.

===Equatorial anomaly===
[[Image:Diurnal ionospheric current.jpg|thumb|upright=1.25|Electric currents created in sunward ionosphere.]]
Within approximately ± 20 degrees of the ''magnetic equator'', is the ''[[equator]]ial anomaly.''<ref name=":0">{{Cite journal |last1=Andreeva |first1=E. S. |last2=Franke |first2=S. J. |last3=Yeh |first3=K. C. |last4=Kunitsyn |first4=V. E. |date=2000-08-15 |title=Some features of the equatorial anomaly revealed by ionospheric tomography |url=https://agupubs.onlinelibrary.wiley.com/doi/10.1029/1999GL003725 |journal=Geophysical Research Letters |language=en |volume=27 |issue=16 |pages=2465–2468 |doi=10.1029/1999GL003725 |issn=0094-8276}}</ref><ref>{{Cite journal |last1=Wu |first1=Tsung-Yu |last2=Liu |first2=Jann-Yenq |last3=Chang |first3=Loren C. |last4=Lin |first4=Chien-Hung |last5=Chiu |first5=Yi-Chung |date=2021-07-19 |title=Equatorial ionization anomaly response to lunar phase and stratospheric sudden warming |journal=Scientific Reports |language=en |volume=11 |issue=1 |pages=14695 |doi=10.1038/s41598-021-94326-x |pmid=34282218 |issn=2045-2322|pmc=8289839 }}</ref> It is the occurrence of a trough in the ionization in the F<sub>2</sub> layer at the equator and crests at about 17 degrees in magnetic latitude.<ref name=":0" /> The [[Earth's magnetic field]] lines are horizontal at the magnetic equator. Solar heating and [[Tide|tidal]] oscillations in the lower ionosphere move plasma up and across the magnetic field lines. This sets up a sheet of electric current in the E region which, with the [[Horizontal plane|horizontal]] magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from the magnetic equator. This phenomenon is known as the ''equatorial fountain''.<ref name=":1">{{Cite web |last=Bridgman |first=Tom |date=2018-01-31 |title=NASA Scientific Visualization Studio {{!}} Interface to Space: The Equatorial Fountain |url=https://svs.gsfc.nasa.gov/4617/ |access-date=2024-09-30 |website=NASA Scientific Visualization Studio |language=english}}</ref>

===Equatorial electrojet===
The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere ([[ionospheric dynamo region]]) ({{convert|100–130|km|mi|sigfig=1|abbr=on}} altitude).{{Citation needed|date=September 2024}} Resulting from this current is an electrostatic field directed west–east (dawn–dusk) in the equatorial day side of the ionosphere. At the magnetic dip equator, where the geomagnetic field is horizontal, this electric field results in an enhanced eastward current flow within ± 3 degrees of the magnetic equator, known as the [[equatorial electrojet]].<ref name=":1" />