Impulsive excitation of ULF waves in the three-dimensional dipole model: The initial results

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JA02349· OSTI ID:5376239

Lee, Donghun; Lysak, R L ^[1]

---

1. Univ. of Minnesota, Minneapolis (USA)

Impulsively excited ULF waves are studied in the three-dimensional dipole magnetosphere. The properties of coupled compressional and transverse wave fields are found to depend on the longitudinal size of the impulse which is assumed at the magnetopause. The distribution of energy density and the wave spectra are shown for different meridians. The authors study how compressional waves propagate in the three-dimensional space and excite the corresponding field line resonances, and how the impulse produces ULF waves with many azimuthal wave numbers m. The results suggest that, as the longitudinal width of the impulse becomes larger at the magnetopause, strong field line resonances are likely to be found with the lower m. On the contrary, an impulse which is narrow in longitude may excite the ULF waves with relatively high m. They examine the propagation of both compressional and transverse waves in the azimuthal direction. The numerical results indicate that transverse waves as well as compressional waves are inclined to have harmonic structures in the azimuthal direction, even though it is well known that the Alfven shear modes become one-dimensional modes along the field lines in the absence of coupling. The structures and coupling of global compressional and toroidal standing waves are also investigated and compared with the previous two-dimensional results.

• OSTI ID: 5376239
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:A3; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPARATIVE EVALUATIONS
DATA
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ENERGY DENSITY
EVALUATION
HYDROMAGNETIC WAVES
INFORMATION
MAGNETOPAUSE
MATHEMATICAL MODELS
MATHEMATICS
NUMERICAL ANALYSIS
NUMERICAL DATA
SHEAR
STANDING WAVES
THEORETICAL DATA
THREE-DIMENSIONAL CALCULATIONS
WAVE PROPAGATION