부산대학교 도서관

We present an interpretation of the recent Daniel K. Inouye Solar Telescope (DKIST) observations of propagating wavefronts in the lower solar atmosphere. Using MPS/University of Chicago MHD (MURaM) radiative magnetohydrodynamic simulations spanning solar photosphere, overshoot region, and lower chromosphere, we identify three acoustic-wave source mechanisms, each occurring at a different atmospheric height. We synthesize the DKIST Visible Broadband Imager (VBI) G-band, blue-continuum, and CaIIK signatures of these waves at high spatial and temporal resolution, and conclude that the wavefronts observed by DKIST likely originate from acoustic sources at the top of the solar photosphere overshoot region and in the chromosphere proper. The overall importance of these local sources to the atmospheric energy and momentum budget of the solar atmosphere is unknown, but one of the excitation mechanism identified (upward propagating shock interaction with down-welling chromospheric plasma resulting in acoustic radiation) appears to be an important shock dissipation mechanism. Additionally, the observed wavefronts may prove useful for ultra-local helioseismological inversions and promise to play an important diagnostic role at multiple atmospheric heights.
Comment: For associated video (mp4) files see https://drive.google.com/file/d/1vWrXVsaazyk--0WSaFXp_shNrZug0cu7/view?usp=drive_link, https://drive.google.com/file/d/12VL2O2O5QztxUVxyB0HqNeGdnKH-ti2Y/view?usp=drive_link, and https://drive.google.com/file/d/1ARmq-m7UTHofPAuQf-p4_9yooRFaJUe9/view?usp=drive_link