Depth of the chromospheric resonant cavity

Determine the depth of the solar chromospheric resonant cavity, including the atmospheric heights at which wave propagation transitions to standing-wave behavior in pore and sunspot atmospheres.

Background

The paper identifies resonant nodes and mixed standing and propagating waves in the chromosphere of a solar pore. Although nearly pure standing oscillations are detected at some locations and times, wave propagation persists in the lower atmospheric layers sampled by the wings of the Hα line, while other observations have reported standing oscillations in upper-photospheric and low-chromospheric layers. These differing observational results leave the vertical extent, or depth, of the resonant cavity unresolved.

Resolving this problem would establish how far downward the chromospheric resonator extends and would clarify how the cavity structure varies between pores, sunspots, and different atmospheric regions or wave-amplitude regimes.