Editing Magnetosphere (section)

==Structure and behavior==
The structure of magnetospheres are dependent on several factors: the type of astronomical object, the nature of sources of [[Plasma (physics)|plasma]] and [[momentum]], the [[frequency|period]] of the object's spin, the nature of the axis about which the object spins, the axis of the magnetic dipole, and the magnitude and direction of the flow of [[solar wind]].

The planetary distance where the magnetosphere can withstand the solar wind pressure is called the Chapman–Ferraro distance. This is usefully modeled by the formula wherein <math>R_{\rm P}</math> represents the radius of the planet, <math>B_{\rm surf}</math> represents the magnetic field on the surface of the planet at the equator, <math>V_{\rm SW}</math> represents the [[velocity]] of the solar wind, <math>\rho</math> is the particle density of solar wind, and <math>\mu_{0}</math> is the [[vacuum permeability]] constant:

:<math>R_{\rm CF}=R_{\rm P} \left( \frac{B_{\rm surf}^2}{\mu_{0} \rho V_{\rm SW}^2} \right) ^{\frac{1}{6}}</math>

A magnetosphere is classified as "intrinsic" when <math>R_{\rm CF} \gg R_{\rm P}</math>, or when the primary opposition to the flow of solar wind is the magnetic field of the object. [[Mercury (planet)|Mercury]], Earth, [[Jupiter]], [[Ganymede (moon)|Ganymede]], [[Saturn]], [[Uranus]], and [[Neptune]], for example, exhibit intrinsic magnetospheres. A magnetosphere is classified as "induced" when <math>R_{\rm CF} \ll R_{\rm P}</math>, or when the solar wind is not opposed by the object's magnetic field. In this case, the solar wind interacts with the atmosphere or ionosphere of the planet (or surface of the planet, if the planet has no atmosphere). [[Venus]] has an induced magnetic field, which means that because Venus appears to have no [[Dynamo theory|internal dynamo effect]], the only magnetic field present is that formed by the solar wind's wrapping around the physical obstacle of Venus (see also [[Atmosphere of Venus#Induced magnetosphere|Venus' induced magnetosphere]]). When <math>R_{\rm CF} \approx R_{\rm P}</math>, the planet itself and its magnetic field both contribute. It is possible that [[Mars]] is of this type.<ref>{{cite journal|last1=Blanc|first1=M.|last2=Kallenbach|first2=R.|last3=Erkaev|first3=N.V.|title=Solar System Magnetospheres|journal=Space Science Reviews|volume=116|date=2005|issue=1–2|pages=227–298|doi=10.1007/s11214-005-1958-y|bibcode=2005SSRv..116..227B |s2cid=122318569}}</ref>

===Dawn-dusk asymmetry===
When viewed from the Sun, a celestial body's orbital motion can compress its otherwise symmetrical magnetosphere slightly, and stretch it out in the direction opposite its motion (in Earth's example, from west to east). This is known as ''dawn-dusk asymmetry''. <ref name="Wiley 3017">{{cite book |editor-first1=Stein|editor-last1=Haaland|editor-first2=Andrei|editor-last2=Runov|editor-first3=Colin|editor-last3=Forsyth
| title=Dawn-Dusk Asymmetries in Planetary Plasma Environments |series=Geophysical Monograph Series | publisher=Wiley | date=October 6, 2017 | isbn=978-1-119-21632-2 | doi=10.1002/9781119216346 | url=https://agupubs.onlinelibrary.wiley.com/doi/book/10.1002/9781119216346 | access-date=April 9, 2025 }}</ref><ref name="Tromsø 2023">{{cite journal | last1=Oyama | first1=Shin-ichiro | last2=Aikio | first2=Anita | last3=Sakanoi | first3=Takeshi | last4=Hosokawa | first4=Keisuke | last5=Vanhamäki | first5=Heikki | last6=Cai | first6=Lei | last7=Virtanen | first7=Ilkka | last8=Pedersen | first8=Marcus | last9=Shiokawa | first9=Kazuo | last10=Shinbori | first10=Atsuki | last11=Nishitani | first11=Nozomu | last12=Ogawa | first12=Yasunobu | title=Geomagnetic activity dependence and dawn-dusk asymmetry of thermospheric winds from 9-year measurements with a Fabry–Perot interferometer in Tromsø, Norway | journal=Earth, Planets and Space | volume=75 | issue=1 | date=May 5, 2023 | issn=1880-5981 | doi=10.1186/s40623-023-01829-0 | doi-access=free | page=70| bibcode=2023EP&S...75...70O }}</ref><ref name="Liu et al 2019">{{cite journal | last1=Liu | first1=Yi-Hsin | last2=Li | first2=T. C. | last3=Hesse | first3=M. | last4=Sun | first4=W. J. | last5=Liu | first5=J. | last6=Burch | first6=J. | last7=Slavin | first7=J. A. | last8=Huang | first8=K. | title=Three-Dimensional Magnetic Reconnection With a Spatially Confined X-Line Extent: Implications for Dipolarizing Flux Bundles and the Dawn-Dusk Asymmetry | journal=Journal of Geophysical Research: Space Physics | volume=124 | issue=4 | date=2019 | issn=2169-9380 | doi=10.1029/2019JA026539 | doi-access=free | pages=2819–2830 | arxiv=1901.10195 | bibcode=2019JGRA..124.2819L }}</ref>