【タイトル】Signature of Chromospheric Downflows in Acoustic Travel-time Measurements from Hinode
【発表者(敬称略)】長島 薫（総研大 D2・三鷹、指導教員 関井 隆)
We report on detection of chromospheric downflows in two emerging magnetic flux regions by time-distance helioseismology analysis. We use both chromospheric intensity oscillation data in Ca ii H line and photospheric Dopplergrams in Fe i 557.6nm line observed by Solar Optical Telescope (SOT) onboard Hinode for our analyses. By crosscorrelating oscillation signals, we have detected a travel-time anomaly in these emergingflux regions; outward travel time is about a half minute shorter than inward travel time in the Ca ii H data but not in the Fe i data. This can be interpreted as a signature of downflows in chromosphere.
The downflow speed is estimated at ～ 8 km/s, which is consistent with the typical picture of emerging-flux regions. This result demonstrates a new possibility of studying chromospheric flows by time-distance analysis.