TY - GEN T1 - Photospheric high-frequency acoustic power excess in sunspot umbra: signature of magneto-acoustic modes T2 - arXiv PY - 2009/09/29 AU - Zharkov S AU - Shelyag S AU - Fedun V AU - Erdélyi R AU - Thompson MJ ED - Y2 - 2024/12/22 ER -