Date: Summer 2012
I know that Earth, and other planets like Jupiter have an Ionosphere. I was told that Jupiter's Ionosphere is the biggest entity in the Solar System. My question is: Does the Sun have an Ionosphere? If not, then why?...Because, like Earth and Jupiter, the Sun has electromagnetic poles, and an obviously active core. Would an active core and electromagnet poles go hand-in-hand with an Ionosphere?
Thank you for your question! No, the Sun does not have an ionosphere, it creates an ionosphere surrounding other planets.
The Sun, as a part of its thermonuclear reactions produces an abundance if ions called the Solar Wind. The Solar wind is H and He ions streaming outward into space. The Sun produces its own ions.
Those ions are somewhat deflected by Earth's magnetosphere and its field, creating a distinct layer of ionized atmosphere from about 50 miles - 650 miles above Earth's surface. That layer is the highly electromagnetically active layer, the ionosphere. Earth's ionosphere is a layer of atmosphere that absorbs Solar radiation, the Solar Wind, and the Sun's magnetic field and in effect protects the surface from those ionizing events. Storms on the Sun create perturbations in the Solar Wind, which we notice here as Aurorae.
Jupiter has an intense magnetic influence, but not necessarily from a solid core, it is a gas planet. The extreme gravity produces superconductive metallic Hydrogen throughout the planet. This suggests the magnetic field of Jupiter may be generated at the surface, perhaps by a form of cyclotron maser effect.
The Sun is actively storming now, so go out, watch an Aurora and see our ionosphere in action!
Peter E. Hughes, Ph.D. Milford, NH
I think you may be confusing magnetosphere and ionosphere. Ionospheres come from ionized particles in the upper atmosphere of planets and moons. So the required ingredients for an ionosphere are: UV radiation from the Sun (to ionize the particles and keep them ionized), molecules in the upper atmosphere that can absorb UV light and then break apart - most likely as positive ions and free electrons. Most planets (and some moons) with an atmosphere of ionizable gases do have an ionosphere. On the other hand, magnetospheres are developed from "active cores" (the movement of the core is theorized to result in the formation of a magnetic field) that then control the movement of gases in the upper atmosphere. We observe such magnetic fields when the combination of the solar wind is deflected by the magnetic filed of the planet.
In both cases though it is counter to the definition to say that the Sun may have a magnetosphere or an ionosphere. The ionized particles of an ionosphere is developed from interactions with UV from the Sun. While the particles on the Sun's surface can be said to interact with the Sun's own UV, the fact is practically all of the Sun's surface is plasma and ionized gases - so technically, there is no distinguishing boundary between the Sun and its ionized gases. While the Sun does have a very complex magnetic field, there is no boundary being formed by the solar wind and this magnetic field - since they are from the same source.
Greg (Roberto Gregorius)
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Update: December 2011