Magnetospheric filter effect for Pc 3 Alfven mode waves

Technical Report · Thu Jun 01 04:00:00 EDT 1995

OSTI ID:200630

Zhang, X; Comfort, R H; Gallagher, D L; Green, J L; Musielak, Z E; Moore, T E

The authors present a ray-tracing study of the propagation of Pc 3 Alfven mode waves originating at the dayside magnetopause. This study reveals interesting features of magnetospheric filter effect for these waves. Pc 3 Alfven mode waves cannot penetrate to low Earth altitudes unless the wave frequency is below approximately 30 mHz. Configurations of the dispersion curves and the refractive index show that the gyroresonance and pseudo-cutoff introduced by the heavy ion O(+) block the waves. When the O(+) concentration is removed from the plasma composition, the barriers caused by the O(+) no longer exist, and waves with much higher frequencies than 30 mHz can penetrate to low altitudes. The result that the 30 mHz or lower frequency Alfven waves can be guided to low altitudes agrees with ground-based power spectrum observation at high altitudes.

• Research Organization: National Aeronautics and Space Administration, Huntsville, AL (United States). George C. Marshall Space Flight Center
• OSTI ID: 200630
• Report Number(s): N--96-19526; NASA-CR--199998; NAS--1.26:199998; PAPER--95JA00276; NIPS--96-07102; CNN: NAGW-1630; NAG8-239; NSF ATM-91-19580; RTOP 432-20-00
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALFVEN WAVES
EARTH MAGNETOSPHERE
FILTRATION
HYDROMAGNETIC WAVES
MAGNETOPAUSE
MILLI HZ RANGE
OXYGEN IONS
REFRACTIVE INDEX
WAVE PROPAGATION