Jump to navigation Jump to search
- The quality of being helical.
- (physics, fluid mechanics, electrodynamics) Any of certain measures of the extent to which vortex lines (in fluid flow) or field lines (in a magnetic or electromagnetic field) kink and twist and/or link and coil around one another.
- 1991, E. Levich, L. Shtilman, “Helicity Fluctuations and Coherence in Developed Turbulence”, in D. Schertzer, S. Lovejoy, editors, Non-Linear Variability in Geophysics: Scaling and Fractals, Kluwer Academic Publishers, page 18:
- The conjecture made in Tsinober and Levich (1983) was that coherent structures should possess a significant coherent helicity.
- 1995, G. E. Marsh, “2: Helicity and Electrodynamic Field Topology”, in Terence William Barrett, Dale M. Grimes, editors, Advanced Electromagnetism: Foundations, Theory and Applications, World Scientific, page 62:
- The helicity associated with the writhing number is obtained by observing that a torus with twist number ±1 may be distorted into a figure-8 configuration which appears untwisted. […] Note that at each step the total helicity, consisting of the sum of twist, kink, and link helicities, is conserved.
- 2001, Mitchell A. Berger, “Measures of Topological Structure in Magnetic Fields”, in Renzo L. Ricca, editor, An Introduction to the Geometry and Topology of Fluid Flows, Springer, page 249:
- Thus the total helicity H equals the sum of the entries in a matrix Hij. If N is large then there will be many more mutual helicity terms. In this case ignoring the self helicities (if they are difficult to observe) may only give a small error.
- 2016, Eric G. Blackman, “Magnetic Helicity and Large Scale Magnetic Fields: A Primer”, in Andre Balogh, Andrei Bykov, Jonathan Eastwood, Jelle Kaastra, editors, Multi-scale Structure Formation and Dynamics in Cosmic Plasmas, Springer,, page 72:
- Now conservation of helicity is maintained: the writhe of the loops in the second panel is compensated for by the opposite sign of the twist helicity along the loops.
- (physics, quantum mechanics) The quantized spin component of a moving particle along the direction of its motion.
physics: quantized spin component