Results 231 to 240 of about 1,274,578 (287)

Group velocity of whistlers

Journal of Geophysical Research, 1976
The dispersion relation of waves in a cold magnetoplasma can be given in the form ..sigma../sub i//sub 0/ /sub p/ Au(k) ..omega..'=0, where ..omega.. is the frequency and the coefficients A/sub i/ are functions of the wave vector k. The group velocity V/sub g/ can be expressed as V/sub g/=-..sigma../sub i//sub 0/ p (partialA/sub i//partialk) ..omega ...
K. M. Johansen, Egil Leer
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Sensory group la proximal conduction velocity

Muscle & Nerve, 1984
AbstractThe fastest median and ulnar velocities derived by recording motor and mixed nerve action potentials, F waves, H‐reflexes, and somatosensory evoked potentials (SEPs) were compared. H‐reflex recording was facilitated by employing selective group la excitation during voluntary muscular contraction.
A, Eisen, M, Hoirch, J, White, D, Calne
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Group velocity of light in biaxial crystals

Applied Optics, 2021
Based on the wave vector surface, we have derived the analytical expressions for the group velocity of light traveling in an optically biaxial crystal in an arbitrary direction. Our formulas are in terms of either the wave vector direction or the ray direction.
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Group velocity matching in optical fibers

Optics Letters, 1977
Group velocity matching has been observed in an optical fiber. The matching occurred in a fiber Raman oscillator pumped by mode-locked laser pulses. The group velocity difference between pump and Stokes pulses due to material dispersion was compensated for by the group delay between two different waveguide modes.
C, Lin, R H, Stolen, R K, Jain
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Raman solitons with group velocity dispersion

Physical Review E, 2006
We consider the coupled propagation of the pump and Stokes waves in a Raman active medium accounting for the group velocity walk off and group velocity dispersion. Interplay of the Raman coherence and the dispersion can lead to the formation of a complete band gap in the spectrum of linear waves consisting of the two consecutive subgaps located at ...
D V, Skryabin, A V, Yulin
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Generalized Group Velocity Description

Frontiers in Optics 2012/Laser Science XXVIII, 2012
The group velocity description of dispersive pulse propagation, strictly valid for lossless media, is generalized to include dispersive attenuative media, reducing to the group velocity approximation while describing the precursor fields in the appropriate limits.
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Group velocity control by quadratic nonlinear interactions

2005 IEEE LEOS Annual Meeting Conference Proceedings, 2005
We give direct experimental evidence that the group velocity of ultrashort pulses can be controlled through chi(2)-cascaded interactions, under the condition of large group-velocity mismatch. The group velocity can be finely tuned by acting on pulse intensity and phase mismatch.
De Angelis, C.(a), Baronio, F.(a), Marangoni, M.(b), Manzoni, C.(b), Ramponi, R.(b), Cerullo, G.(b), Kitamura, K.(c)   +13 more
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The four-dimensional group velocity

Soviet Physics Uspekhi, 1978
The advantages of using the 4-dimensional group velocity are demonstrated. After first giving its purely kinematic definition for an arbitrary wave field, the discussion turns to packets of electromagnetic waves in electrically and magnetically anisotropic media which possess space-time dispersion and are smoothly nonuniform in space and slowly varying
V.G. Polevoi, S.M. Rytov
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The Group Velocity Approximation

2009
Because of its mathematical simplicity and direct physical interpretation, the group velocity approximation has gained widespread use in the physics, engineering, and mathematical science communitites. However, the fundamental assumptions that are used to obtain this description are violated when either the loss component of the material dispersion ...
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Group-Phase Velocity Demonstrator

American Journal of Physics, 1953
The speed with which the concepts of group velocity, phase velocity, and beats are grasped, integrated, and retained can be materially aided with the following simple demonstration apparatus.
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