Coupled Hydromagnetic Modes: Initial Value Problems.
Physical science research papers,
AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS
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Before micropulsations can be utilized as a diagnostic tool, the critical theoretical problem of coupled hydromagnetic modes must be appreciated. Several alternative analyses of the steady state solutions of coupled modes have been proposed. In determining which, if any, steady state solution is of physical significance, the manner in which the hydromagnetic system evolves from an initial disturbance would be decisive. The basic initial value problems are those of field line excitation and relaxation. At present, these problems are investigated best by using a mechanical analogue of the resonant interaction between hydromagnetic modes. The transient response as well as the transmission and reflection coefficients have been calculated for the excitation problem. Analysis of the relaxation problem indicates that the characteristic frequency of the radiated signal need not be identical to the field line frequency. For the case treated, the frequency is always less and the waveform can appear as a single pulse. Results suggest that damped oscillations should be the characteristic signature of micropulsations propagated to low latitudes. Author
- Atmospheric Physics
- Plasma Physics and Magnetohydrodynamics