Hybrid Alfven resonant mode generation in the magnetosphere-ionosphere coupling system
- National Institute for Fusion Science, Oroshi-cho 322-6, Toki, Gifu 509-5292 (Japan)
Feedback unstable Alfven waves involving global field-line oscillations and the ionospheric Alfven resonator (IAR) were comprehensively studied to clarify their properties of frequency dispersion, growth rate, and eigenfunctions. It is discovered that a new mode called here the hybrid Alfven resonant (HAR) mode can be destabilized in the magnetosphere-ionosphere coupling system with a realistic Alfven velocity profile. The HAR mode found in a high frequency range over 0.3 Hz is caused by coupling of IAR modes with strong dispersion and magnetospheric cavity resonances. The harmonic relation of HAR eigenfrequencies is characterized by a constant frequency shift from those of IAR modes. The three modes are robustly found even if effects of two-fluid process and ionospheric collision are taken into account and thus are anticipated to be detected by magnetic field observations in a frequency range of 0.3-1 Hz in auroral and polar-cap regions.
- OSTI ID:
- 22072593
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 10; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Anisotropic Alfven-ballooning modes in the Earth`s magnetosphere
Coupling instability of the shear Alfven wave in the magnetosphere with the ionospheric ion drift wave 2. Numerical analysis