Research Information System
Advances in Space Research, 2026 (SCI-Expanded, Scopus)
We investigate frequency-dependent velocity coupling sampled in the H(Formula presented) line wings above photospheric bright points (BPs), using simultaneous observations at two spectral positions ((Formula presented) mÅand (Formula presented) mÅ). Line-of-sight (LOS) velocities are derived via the lambdameter method and analyzed using wavelet power, coherence, and phase-difference diagnostics.The five BPs exhibit dominant variability in the 2–3min and 5–7min period ranges, although the relative contribution of these bands differs among individual elements. The coherence spectra reveal intervals of enhanced coupling between the two spectral samplings, characterized by small and temporally varying phase differences.Rather than indicating a single dominant oscillatory mode or steady vertical propagation between discrete atmospheric layers, the combined diagnostics point to a structured and time-dependent dynamical response within magnetically concentrated regions. The results demonstrate that multi-offset H(Formula presented) velocity measurements provide a sensitive diagnostic of frequency-dependent dynamical coupling associated with small-scale magnetic elements.