Helioseismic Signature of Chromospheric Downflows in Acoustic Travel-Time Measurements from Hinode

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dc.creatorNagashima, Kaori
dc.creatorSekii, Takashi
dc.creatorKosovichev, Alexander G.
dc.creatorZhao, Junwei
dc.creatorTarbell, Theodore D.
dc.date2009-03-07
dc.date.accessioned2026-07-07T12:50:47Z
dc.date.available2026-07-07T12:50:47Z
dc.descriptionWe report on a signature of chromospheric downflows in two emerging-flux regions detected by time-distance helioseismology analysis. We use both chromospheric intensity oscillation data in the Ca II H line and photospheric Dopplergrams in the Fe I 557.6nm line obtained by Hinode/SOT for our analyses. By cross-correlating the Ca II oscillation signals, we have detected a travel-time anomaly in the plage regions; outward travel times are shorter than inward travel times by 0.5-1 minute. However, such an anomaly is absent in the Fe I data. These results can be interpreted as evidence of downflows in the lower chromosphere. The downflow speed is estimated to be below 10 km/s. This result demonstrates a new possibility of studying chromospheric flows by time-distance analysis.
dc.description9 pages, 4 figures, accepted for publication in ApJL
dc.identifierhttps://arxiv.org/abs/0903.1323
dc.identifierhttp://arxiv.org/abs/0903.1323
dc.identifierApJ 694 (2009) L115-L119
dc.identifierdoi:10.1088/0004-637X/694/2/L115
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/222791
dc.subjectSolar and Stellar Astrophysics
dc.titleHelioseismic Signature of Chromospheric Downflows in Acoustic Travel-Time Measurements from Hinode
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