Interplanetary Magnetic Field
- Interplanetary Magnetic Field
The Interplanetary Magnetic Field (IMF) is the term for the Sun’s magnetic field carried by the solar wind among the planets of the Solar System.
[
heliospheric current sheet is a three-dimensional form of a Parker spiral that results from the influence of the Sun's rotating magnetic field on the plasma in the interplanetary medium. [http://wso.stanford.edu/gifs/helio.gif] ] Since the solar wind is a plasma, it has the characteristics of a plasma, rather than a simple gas. For example, it is highly electrically conductive so that magnetic field lines from the Sun are carried along with the wind. The dynamic pressure of the wind dominates over the magnetic pressure through most of the solar system (or heliosphere), so that the magnetic field is pulled into an Archimedean spiral pattern (the Parker spiral) by the combination of the outward motion and the Sun's rotation. Depending on the hemisphere and phase of the solar cycle, the magnetic field spirals inward or outward; the magnetic field follows the same shape of spiral in the northern and southern parts of the heliosphere, but with opposite field direction. These two magnetic domains are separated by a two current sheet (an electric current that is confined to a curved plane). This heliospheric current sheet has a similar shape to a twirled ballerina skirt, and changes in shape through the solar cycle as the Sun's magnetic field reverses about every 11 years.
The plasma in the interplanetary medium is also responsible for the strength of the Sun's magnetic field at the orbit of the Earth being over 100 times greater than originally anticipated. If space were a vacuum, then the Sun's 10-4 tesla magnetic dipole field would reduce with the cube of the distance to about 10-11 tesla. But satellite observations show that it is about 100 times greater at around 10-9 tesla. Magnetohydrodynamic (MHD) theory predicts that the motion of a conducting fluid (e.g. the interplanetary medium) in a magnetic field, induces electric currents which in turn generates magnetic fields, and in this respect it behaves like a MHD dynamo.
ee also
* Solar wind
* magnetosphere
References
* [http://www.spaceweather.com/glossary/imf.html spaceweather.com]
* [http://pluto.space.swri.edu/image/glossary/IMF.html Southwest Research Institute]
Wikimedia Foundation.
2010.
Look at other dictionaries:
Magnetic field of celestial bodies — See also Earth s magnetic field The magnetic field of a rotating body of conductive gas or liquid develops self amplifying electric currents, and thus a self generated magnetic field, due to a combination of differential rotation (different… … Wikipedia
Mercury's magnetic field — Magnetosphere of Mercury Graph showing relative strength of Mercury s magnetic field. Discovery[1] … Wikipedia
Earth's magnetic field — Computer simulation of the Earth s field in a normal period between reversals.[1] The tubes represent magnetic field lines, blue when the field points towards the center and yellow when away. The rotation axis of the Earth is centered and… … Wikipedia
Dipole model of the Earth's magnetic field — Plot showing field lines (which, in three dimensions would describe shells ) for L values 1.5, 2, 3, 4 and 5 using a dipole model of the Earth s magnetic field The dipole model of the Earth s magnetic field is a first order approximation of the… … Wikipedia
solar magnetic field — noun the magnetic field of the sun • Hypernyms: ↑magnetic field, ↑magnetic flux, ↑flux • Part Holonyms: ↑interplanetary medium … Useful english dictionary
Magnetic reconnection — is a physical process in highly conducting plasmas in which the magnetic topology is rearranged and magnetic energy is converted to kinetic energy, thermal energy, and particle acceleration. Magnetic reconnection occurs on timescales intermediate … Wikipedia
interplanetary medium — ▪ astronomy thinly scattered matter that exists between the planets and other bodies of the solar system, as well as the forces (e.g., magnetic and electric) that pervade this region of space. The material components of the interplanetary… … Universalium
Interplanetary spaceflight — or interplanetary travel is travel between planets within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the Solar System. Current achievements in interplanetary travel Remotely… … Wikipedia
Interplanetary medium — [ heliospheric current sheet results from the influence of the Sun s rotating magnetic field on the plasma in the interplanetary medium. [http://quake.stanford.edu/ wso/gifs/HCS.html] ] The interplanetary medium is the material which fills the… … Wikipedia
geomagnetic field — Magnetic field associated with the Earth. It is essentially dipolar (i.e., it has two poles, the northern and southern magnetic poles) on the Earth s surface. Away from the surface, the field becomes distorted. Most geomagnetists explain the… … Universalium
