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Context. The carbon monoxide (CO) molecular line at around 46655 A in solar infrared spectra is often used to investigate the dynamic behavior of the cold heart of the solar atmosphere, i.e., sunspot oscillation, especially at the sunspot…

Solar and Stellar Astrophysics · Physics 2020-10-28 D. Li , X. Yang , X. Y. Bai , J. T. Su , Z. J. Ning , W. Cao , Y. Y. Deng

Switchbacks (rotations of the magnetic field) are observed on the Parker Solar Probe. Their evolution, content, and plasma effects are studied in this paper. The solar wind does not receive a net acceleration from switchbacks that it…

We investigate the fine structure of the sunspot penumbra by means of a model that allows for a flux tube in horizontal pressure balance with the magnetic background atmosphere in which it is embedded. We apply this model to…

Astrophysics · Physics 2009-11-10 J. M. Borrero , A. Lagg , S. K. Solanki , M. Collados

Coronal fan loops rooted in sunspot umbra show outward propagating waves with subsonic phase speed and period around 3-min. However, their source region in the lower atmosphere is still ambiguous. We performed multi-wavelength observations…

Solar and Stellar Astrophysics · Physics 2023-09-06 Ananya Rawat , Girjesh Gupta

High-resolution broadband filtergrams of active region NOAA 11271 in Ca ii H and G band were obtained with the Solar Optical Telescope on board Hinode to identify the physical driver responsible for the dynamic and small-scale chromospheric…

Solar and Stellar Astrophysics · Physics 2015-06-19 Rohan E. Louis , Christian Beck , Kiyoshi Ichimoto

We present the results of multi wavelength, co-spatial and near co-temporal observations of jets above a sunspot light bridge. The data were obtained with the Solar Optical Telescope (SOT) on board Hinode, the Interface Region Spectrograph…

Solar and Stellar Astrophysics · Physics 2015-05-12 Lokesh Bharti

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

The solar atmosphere is a dynamic environment, constantly evolving to form a wide range of magnetically dominated structures (coronal loops, spicules, prominences, etc.) which cover a significant percentage of the surface at any one time.…

Solar and Stellar Astrophysics · Physics 2013-06-06 R. Erdélyi , A. Hague , C. J. Nelson

Here we review the recent progress made in the detection, examination, characterisation and interpretation of oscillations manifesting in small-scale magnetic elements in the solar photosphere. This region of the Sun's atmosphere is…

Solar and Stellar Astrophysics · Physics 2016-03-09 David B. Jess , Gary Verth

We investigate the thermal and kinematic configuration of a sunspot penumbra using very high spectral and spatial resolution intensity profiles of the non-magnetic Fe I 557.6 nm line. The dataset was acquired with the 2D solar spectrometer…

Astrophysics · Physics 2007-05-23 L. R. Bellot Rubio , R. Schlichenmaier , A. Tritschler

The presence of intense magnetic fields in and around sunspots is expected to modify the solar structure and oscillation frequencies. Applying the ring diagram technique to data from the Michelson Doppler Imager (MDI) on board the Solar and…

Astrophysics · Physics 2009-11-07 S. P. Rajaguru , Sarbani Basu , H. M. Antia

Helioseismic and magnetohydrodynamic waves are abundant in and above sunspots. Through cross-correlating oscillation signals in the photosphere observed by the SDO/HMI, we reconstruct how waves propagate away from virtual wave sources…

Solar and Stellar Astrophysics · Physics 2015-08-19 Junwei Zhao , Ruizhu Chen , Thomas Hartlep , Alexander G. Kosovichev

Intensity bursts in ultraviolet (UV) to X-ray wavelengths and plasma jets are typical signatures of magnetic reconnection and the associated impulsive heating of the solar atmospheric plasma. To gain new insights into the process,…

Solar and Stellar Astrophysics · Physics 2021-12-15 L. P. Chitta , S. K. Solanki , H. Peter , R. Aznar Cuadrado , L. Teriaca , U. Schühle , F. Auchère , D. Berghmans , E. Kraaikamp , S. Gissot , C. Verbeeck

Our observations of the quiet Sun with the NST have yielded unanticipated results on smal-scale solar dynamic. Althought small-scale solar dynamic have been well-studied, the NST is enabling us to probe finer scale dynamic exploiting higher…

Solar and Stellar Astrophysics · Physics 2009-12-23 Aleksandra Andic

We use high spatial and temporal resolution observations, simultaneously obtained with the New Vacuum Solar Telescope and Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, to investigate the high-frequency…

Solar and Stellar Astrophysics · Physics 2018-03-28 Feng Wang , Hui Deng , Bo Li , Song Feng , Xianyong Bai , Linhua Deng , Yunfei Yang , Zhike Xue , Rui Wang

We analyze the effect of a sunspot in its quiet surroundings applying a helioseismic technique on almost three years of Helioseismic and Magnetic Imager (HMI) observations obtained during solar cycle 24 to further study the sunspot…

Solar and Stellar Astrophysics · Physics 2018-05-23 M. Cristina Rabello-Soares , Richard S. Bogart , Philip H. Scherrer

We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…

Previous helioseismology of sunspots has been sensitive to both the structural and magnetic aspects of sunspot structure. We aim to develop a technique that is insensitive to the magnetic component so the two aspects can be more readily…

Solar and Stellar Astrophysics · Physics 2018-06-07 T. L. Duvall , P. S. Cally , D. Przybylski , K. Nagashima , L. Gizon

We investigate the magnetic field of a sunspot in the upper chromosphere and compare it to the field's photospheric properties. We observed the main leading sunspot of the active region NOAA 11124 on two days with the Tenrife Infrared…

Solar and Stellar Astrophysics · Physics 2017-08-23 Jayant Joshi , Andreas Lagg , Johann Hirzberger , Sami K. Solanki

We use spectro-polarimetric data recorded by Hinode to analyze the magnetic field configuration of a part of a sunspot (AR 10923) where a bundle of penumbral filaments are intruding into its umbra. We want to explore the role of the sunspot…

Solar and Stellar Astrophysics · Physics 2024-05-15 Hashem Hamedivafa