Modulation instability of spiral density waves: high-order nonlinearity effects

Journal Article · Fri Mar 01 04:00:00 EST 1985 · Sov. Astron. (Engl. Transl.); (United States)

OSTI ID:5146272

Korchagin, V I; Korchagin, P I

The evolution of the envelope of a tightly wound spiral density wave in a gravitating gaseous disk is investigated, including nonlinear terms to fifth order in the amplitude. These terms in the expansion of the fundamental harmonic set limits on the applicability of the weakly nonlinear approximation, and demonstrate that the group velocity depends on the wave amplitude. For a disk with solar-neighborhood parameters and a spiral pattern speed ..cap omega../sub p/ = 20 km sec/sup -1/ kpc/sup -1/, the fifth-order nonlinearity will be significant if the wave amplitude is not too small (sigma-tilde/sigma/sub 0/>30%). One also must allow for fifth-order nonlinearity if the coefficient of the cubic nonlinearity vanishes.

• Research Organization: Institute of Physics, Rostov University
• OSTI ID: 5146272
• Journal Information: Sov. Astron. (Engl. Transl.); (United States), Journal Name: Sov. Astron. (Engl. Transl.); (United States) Vol. 29:2; ISSN SAAJA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
640107 -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
CONFIGURATION
DENSITY
DISTRIBUTION
GALAXIES
GRAVITATION
GRAVITATIONAL INSTABILITY
INSTABILITY
MASS DISTRIBUTION
MODULATION
NONLINEAR PROBLEMS
PHYSICAL PROPERTIES
PLASMA INSTABILITY
SPATIAL DISTRIBUTION
SPIRAL CONFIGURATION