Modulation instability of waves in a magnetized plasma

Miscellaneous · Fri Jan 01 00:00:00 EST 1988

OSTI ID:5595843

Longtin, M C

Modulation instability of finite-amplitude transverse waves in an ideal magnetized plasma with a non-zero sound speed has been investigated theoretically by use of an isentropic two-fluid model. In the first part of this thesis, a perturbation expansion is performed on a circularly polarized, transverse Alfven wave propagating parallel to the constant ambient magnetic field with arbitrary amplitude and with arbitrary frequency {omega}{sub 0}. The result of the perturbation expansion is a sixth-order algebraic dispersion relation in terms of the frequency and wave number perturbations, w and k. The analysis is then limited to the case where {omega}{much lt} {omega}{sub 0} {much lt} {omega}{sub ce}, {omega}{sub ce} being the electron-cyclotron frequency. The resulting fourth-order dispersion relation is examined analytically and numerically and a surface is found that separates modulationally stable and unstable regions in parameter space. In the second part of this thesis, a reductive perturbation expansion of the two-fluid equations is used to derive a nonlinear Schrodinger equation, which describes the time evolution of a modulated, weakly nonlinear, elliptically polarized carrier wave propagating obliquely to the constant ambient magnetic field with frequency wo. Here, the author assumes that wo is negligible compared with {omega}{sub ce} but nonnegligible with {omega}{sub ci}, the ion-cyclotron frequency.

• Research Organization: Dartmouth Coll., Hanover, NH (United States)
• OSTI ID: 5595843
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH MAGNETOSPHERE
WAVE PACKETS
WAVE PROPAGATION
ALFVEN WAVES
ANALYTICAL SOLUTION
COMPARATIVE EVALUATIONS
CYCLOTRON FREQUENCY
DISPERSION RELATIONS
EARTH ATMOSPHERE
INTERACTIONS
ISOTROPY
MAGNETIC FIELDS
MATHEMATICAL MODELS
MODULATION
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
PERTURBATION THEORY
PLASMA
PLASMA WAVES
SCHROEDINGER EQUATION
SOLAR WIND
DIFFERENTIAL EQUATIONS
EQUATIONS
HYDROMAGNETIC WAVES
PARTIAL DIFFERENTIAL EQUATIONS
SOLAR ACTIVITY
WAVE EQUATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena