Propagating Waves and Magnetohydrodynamic Mode Coupling in the Quiet-sun Network

High-cadence multiwavelength optical observations were taken with the Dunn Solar Telescope at the National Solar Observatory, Sacramento Peak, accompanied by Advanced Stokes Polarimeter vector magnetograms. A total of 11 network bright points (NBPs) have been studied at different atmospheric heights using images taken in wave bands centered on Mg i b1 0.4 Å, H , and Ca ii K3. Wavelet analysis was used to study wave packets and identify traveling magnetohydrodynamic waves. Wave speeds were estimated through the temporal crosscorrelation of signals, in selected frequency bands of wavelet power, in each wavelength. Four mode-coupling cases were identified, one in each of four of the NBPs, and the variation of the associated Fourier power with height was studied. Three of the detected mode-coupling, transverse-mode frequencies were observed in the 1.2–1.6 mHz range (mean NBP apparent flux density magnitudes over 99–111 Mx cm 2), with the final case showing 2.0– 2.2 mHz (with 142 Mx cm 2). Following this, longitudinal-mode frequencies were detected in the range 2.6– 3.2 mHz for three of our cases, with 3.9–4.1 mHz for the remaining case. After mode coupling, two cases displayed a decrease in longitudinal-mode Fourier power in the higher chromosphere. Subject headings: MHD — Sun: chromosphere — Sun: magnetic fields — Sun: oscillations — Sun: photosphere