helicity

American  

[hee-lis-i-tee, hi-] / hiˈlɪs ɪ ti, hɪ- /

noun

plural

helicities

1. Physics. the projection of a particle's spin along the direction of its momentum.

2. Biochemistry. (especially of DNA) the character or characteristic of having the form of a helix.

3. Meteorology. the helical rotation in a storm's updraft, the potential of which is a proportional measure of speed, direction, and inflow, factors that are especially critical in the forecasting and mapping of tornadoes.

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helicity British  

/ hɪˈlɪsɪtɪ /

noun

1. physics the projection of the spin of an elementary particle on the direction of propagation

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helicity Scientific  

/ hə-lĭs′ĭ-tē,hē′ /

1. The projection of a particle's spin vector in the direction of its momentum vector, being positive if it points in the same direction, and negative if it points in the opposite direction. Helicity is in effect the handedness, or chirality, of the spin of a particle.

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Other Word Forms

• superhelicity noun

Etymology

Origin of helicity

C20: from _helix + _-ity

Example Sentences

By changing the helicity, or twist, of the circularly polarized pulses, the team could stabilize either the clockwise or anti-clockwise arrangement of electric dipoles.

From Science Daily

Mikic, Z. & Linker, J. Coronal mass ejection: initiation, helicity and flux ropes.

From Nature

Amari, T. & Luciani, J. F. Helicity redistribution during relaxation of astrophysical plasmas.

From Nature

The link between the changes in severe tornado outbreaks and an increase in storm relative helicity is unsurprising but difficult to explain, Brooks says.

From Science Magazine

Many allowed decay modes, which typically involve charmed hadrons and other particles, have angular momentum configurations that are not helicity suppressed.

From Nature