Related papers: Magnetic Properties and Flow Angle of the Inverse …
The photospheric Evershed flow is normally oriented radially outward, yet sometimes opposite velocities are observed not only in the chromosphere but also in the photospheric layers of the penumbra. We study the velocity field in a special…
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…
We analyzed the full Stokes spectra using simultaneous measurements of the photospheric (FeI 630.15 and 630.25 nm) and chromospheric (MgI b2 517.27 nm) lines. The data were obtained with the HAO/NSO Advanced Stokes Polarimeter, about a near…
While it is being conjectured that a chromospheric canopy plays a role in penumbra formation, it has been difficult to find observational evidence of the connectivity between the photosphere and the chromosphere. We investigate the…
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…
The Solar Optical Telescope onboard Hinode revealed the fine-scale structure of the Evershed flow and its relation to the filamentary structures of the sunspot penumbra. The Evershed flow is confined in narrow channels with nearly…
Advanced inversions of high-resolution spectropolarimetric observations of the He I triplet at 1083 nm are used to generate unique maps of the chromospheric magnetic field vector across a sunspot and its superpenumbral canopy. The…
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,…
We describe a scenario for the sunspot magnetic field topology that may account for recent observations of upflows and downflows in penumbrae. According to our conjecture, short narrow magnetic loops fill the penumbral volume. Flows along…
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…
In its first encounter at solar distances as close as r = 0.16AU, Parker Solar Probe (PSP) observed numerous local reversals, or inversions, in the heliospheric magnetic field (HMF), which were accompanied by large spikes in solar wind…
The Evershed flow is a systematic motion of gas that occurs in the penumbra of all sunspots. Discovered in 1909, it still lacks a satisfactory explanation. We know that the flow is magnetized, often supersonic, and that it shows conspicuous…
We present properties of intensity oscillations of a sunspot in the photosphere and chromosphere using G~band and CaIIH filtergrams from Hinode. Intensity power maps as function of magnetic field strength and frequency reveal reduction of…
Assuming that the interchange convection of magnetic flux elements is the physical cause for the existence of filamentary penumbrae in sunspots, we investigate the behavior of an individual fibril embedded in the deep penumbra. The fibril…
Some models for the topology of the magnetic field in sunspot penumbrae predict the existence of field-free or dynamically weak-field regions in the deep Photosphere. To confirm or rule out the existence of weak-field regions in the deepest…
Sunspots, which harbor both magnetic polarities within one penumbra, are called delta-spots. They are often associated with flares. Nevertheless, there are only very few detailed observations of the spatially resolved magnetic field…
Active regions often host large-scale gas flows in the chromosphere presumably directed along curved magnetic field lines. Spectropolarimetric observations of these flows are critical to understanding the nature and evolution of their…
One of the main characteristics of the penumbra of sunspots is the radially outward-directed Evershed flow. Only recently have penumbral regions been reported with similar characteristics to normal penumbral filaments, but with an opposite…
Context. The presence of the moat flow around sunspots is intimately linked to the mere existence of sunspots. Aims. We characterize the moat flow (MF) and Evershed flow (EF) in sunspots to enhance our knowledge of sunspot structures and…
We studied the physical parameters of the penumbra in a large and fully-developed sunspot, one of the largest over the last two solar cycles, by using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and chromospheric Ca II…