相关论文: Properties of Umbral Dots from Stray Light Correct…
The magnetic properties of the umbra-penumbra (UP) boundary of sunspots and the boundary of pores at various evolutionary stages have been characterised using datasets from different instruments. We aim to study the differences between the…
The images of sunspots in sixteen active regions taken at the UCCI Observatory in Grand Cayman during June - November 2015, were used to determine their fractal dimensions using the perimeter-area method for the umbral and the penumbral…
The sunspot penumbra comprises numerous thin, radially elongated filaments that are central for heat transport within the penumbra, but whose structure is still not clear. To investigate the fine-scale structure of these filaments, we…
We present spectropolarimetric measurements of dark-cored penumbral filaments taken with Hinode at a resolution of 0.3". Our observations demonstrate that dark-cored filaments are more prominent in polarized light than in continuum…
The motion of dark striations across bright filaments in a sunspot penumbra has become an important new diagnostic of convective gas flows in penumbral filaments. The nature of these striations has, however, remained unclear. Here we…
We present an analysis of twisting motions in penumbral filaments in sunspots located at heliocentric angles from $30^\circ$ to $48^\circ$ using three time series of blue continuum images obtained by the Broadband Filter Imager (BFI)…
Recent observations of the solar photosphere revealed the presence of elongated filamentary bright structures inside sunspot umbrae, called umbral filaments (UFs). These features differ in morphology, magnetic configuration, and evolution…
Observations with the Interface Region Imaging Spectrograph (IRIS) have revealed numerous sub-arcsecond bright dots in the transition region above sunspots. These bright dots are seen in the 1400\AA{} and 1330\AA{} slit-jaw images. They are…
aims: We study the recently discovered twisting motion of bright penumbral filaments with the aim of constraining their geometry and the associated magnetic field. methods: A large sunspot located $40\degr$ from disk center was observed at…
We analyze several unusual filamentary structures, which appeared in the umbra of one of the sunspots in AR 11302. They do not resemble typical light bridges, neither in morphology, nor in evolution. We analyze data from SDO/HMI to…
We present a method to study the penumbral fine structure using data obtained by the spectropolarimeter onboard HINODE. For the first time, the penumbral filaments can be considered as resolved in spectropolarimetric measurements. This…
Measurements of maximum magnetic flux, minimum intensity, and size are presented for 12 967 sunspot umbrae detected on the NASA/NSO spectromagnetograms between 1993 and 2004 to study umbral structure and strength during the solar cycle. The…
We present a new method to identify large scale filaments and apply it to a cosmological simulation. Using positions of haloes above a given mass as node tracers, we look for filaments between them using the positions and masses of all the…
We detected peaks of oscillatory power at 3 and ~6.5 minutes in the umbra of the central sunspot of the active region NOAA AR 10707 in data obtained in the near infrared (NIR) continuum at 1565.7 nm. The NIR dataset captured umbral dynamics…
We study the temporal evolution of umbral dots (UDs) using measurements from the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope. Scans of the magnetically sensitive 630 nm iron lines were performed under stable…
The analyses of sunspot observations revealed a fundamental magnetic property of the umbral boundary, the invariance of the vertical component of the magnetic field. We aim to analyse the magnetic properties of the umbra-penumbra boundary…
Solar Optical Telescope onboard Hinode observed a sunspot (AR 11836) with two light bridges (LBs) on 31 Aug 2013. We analysed a 2-hour \ion{Ca}{2} H emission intensity data set and detected strong 5-min oscillation power on both LBs and in…
The 3D structure of sunspots has been extensively studied for the last two decades. A recent advancement of the Stokes inversion technique prompts us to revisit the problem. We investigate the global depth-dependent thermal, velocity and…
We present new high-resolution spectro-polarimetric Ca II 8542 observations of umbral flashes in sunspots. At nearly 0.18", and spanning about one hour of continuous observation, this is the most detailed dataset published thus far. Our…
We analyzed the size, intensity, and magnetic field strength of sunspot umbrae to compare the present cycle 24 with the previous one. We used data of the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory and selected…