Jim Fuller edited subsection_Local_Analysis_Many_of__.tex  almost 9 years ago

Commit id: e6641bf9d234e794ff4f62ef8542c0d8fe2cef68

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v_{g,r} = \frac{\omega^2}{N k_\perp} \, .   \end{equation}  For non-negligible buoyancy or magnetic field, the slow and fast magneto-gravity waves have similar characteristics. In the limit of very strong magnetic field or stratification (such that the second term in the square root of equation \ref{eqn:magnetodisp} dominates), we have  \begin{equation}  \label{eqn:magnetodisp3}  k \simeq \pm \sqrt{\frac{N k_\perp}{2 \mu v_A}} \big( 1 \pm i \big).  \end{equation} the wavenumber obtains a large imaginary component.  Therefore, magneto-gravity waves become evanescent in regions of very strong magnetic field. In essence, low frequency waves can reflect off the stiff field lines, similar to low frequency fluid waves reflecting off a solid boundary. The evanescent skin depth is small, with $H_{\rm ev} \sim \sqrt{v_{A}/(N k_\perp)} \ll H$ for realistic field strengths. The transition from propagating to evanescent magneto-gravity waves occurs when  \begin{equation}