Magnetic helicity
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- This page is about helicity in magnetic fields. For fluid mechanical helicity, see helicity
In plasma physics, magnetic helicity is the extent to which a magnetic field "wraps around itself". If magnetic field lines follow the strands of a twisted rope, this configuration would have nonzero magnetic helicity; left handed ropes would have negative values and right handed ropes would have positive values.
Formally,
where
- is the magnetic field strength
- ;
- is the vector potential of
Magnetic helicity is a conserved quantity. It is conserved in electromagnetic fields, even when magnetic reconnection dissipates energy. The concept is useful when considering solar dynamics.
[edit] External links
- A. A. Pevtsov's Helicity on the Web Page
- Mitch Berger's Recent Magnetic Helicity Papers & Reviews Page