Related papers: Supersonic Downflows at the Umbra-Penumbra Boundar…
High resolution spectropolarimetric observations by Hinode reveal the existence of supersonic downflows at the umbra-penumbra boundary of 3 sunspots that was recently reported by Louis et al. (2010). These downflows are observed to be…
To investigate the penumbral plasma flow on a small scale, spectropolari- metric data of sunspots recorded by HINODE was used. Maps of Doppler velocities were created by evaluating the bisector in the line-wing, thereby visualizing the flow…
We study supersonic Evershed downflows in a sunspot penumbra by means of high spatial resolution spectropolarimetric data acquired in the Fe I 617.3 nm line with the CRISP instrument at the Swedish 1-m Solar Telescope. Physical observables,…
The sunspot penumbra is usually observed in the photosphere and it is of particular interest for its magneto-convection which seems to transport the heat from the top of the convection zone into the solar atmosphere. It is well known that…
Sunspot penumbrae show high-velocity patches along the periphery. The high-velocity downflow patches are believed to be the return channels of the Evershed flow. We aim to investigate their structure in detail using Hinode SOT/SP…
Context : Penumbrae are an important characteristic of sunspots, whose formation is intricately related to the nature of sub-photospheric magnetic fields. Aims : We study the formation of a penumbra in a decaying sunspot and compare its…
We study the temporal evolution of downflows observed at the lateral edges of penumbral filaments in a sunspot located very close to the disk center. Our analysis is based on a sequence of nearly diffraction-limited scans of the Fe I 617.3…
Recent high resolution spectropolarimetric observations from Hinode detected the presence of supersonic downflows in a sunspot light bridge (Louis et al. 2009). These downflows occurred in localized patches, close to regions where the field…
A sunspot penumbra is observationally examined to reveal properties of small-scale flow structures and how they are related to the filamentary magnetic structures and the Evershed flow. We also study how the photospheric dynamics is related…
Recently, there have been some reports of unusually strong photospheric magnetic fields (which can reach values of over 7 kG) inferred from Hinode SOT/SP sunspot observations within penumbral regions. These superstrong penumbral fields are…
Context. Fully fledged penumbrae have been widely studied both observationally and theoretically. Yet the relatively fast process of penumbra formation has not been studied closely with high spatial resolution. Aims. We investigate the…
Context. The Evershed effect, a nearly horizontal outflow of material seen in the penumbrae of sunspots in the photospheric layers, is a common characteristic of well-developed penumbrae, but is still not well understood. Even less is known…
We investigate a small-scale ($\approx$ 1.5 Mm along the slit), supersonic downflow of about 90 km s$^{-1}$ in the transition region above the light-bridged sunspot umbra in AR 11836. The observations were obtained with the Interface Region…
We report on high angular resolution, high precision spectropolarimetric measurements of a decaying sunspot. The spot gradually lost its penumbra during the course of three days. In the late stages of evolution where the only remnant of the…
We investigated the vertical penumbral plasma flow on small spatial scales using data recorded by the spectropolarimeter of the solar optical telescope onboard Hinode. To this end we computed maps of apparent Doppler velocities by comparing…
We report the discovery of supersonic downflows in a sunspot light bridge using measurements taken with the spectropolarimeter on board the Hinode satellite. The downflows occur in small patches close to regions where the vector magnetic…
Downflows at supersonic speeds have been observed in the transition region (TR) above sunspots for more than three decades. These downflows are often seen in different TR spectral lines above sunspots. We have performed a statistical…
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…
Recent numerical simulations of sunspots suggest that overturning convection is responsible for the existence of penumbral filaments and the Evershed flow, but there is little observational evidence of this process. Here we carry out a…
We study the velocity structure of penumbral filaments in the deep photosphere to obtain direct evidence for the convective nature of sunspot penumbrae. A sunspot was observed at high spatial resolution with the 1-m Swedish Solar Telescope…