99 citations · 1.3k across the 55 of their papers we have counts for
39 papers · 1 filter
The magnetic origin of the outer boundaries of sunspots
Markus Schmassmann, Nazaret Bello González, Jan Jurčák +1
Context. Sunspot boundaries are commonly outlined by contours of the continuum intensity. However, their magnetic nature has not yet been fully characterised. Aims. We investigate…
Spectral resolution effects on the information content in solar spectra
C. J. Díaz Baso, I. Milić, L. Rouppe van der Voort +1
When interpreting spectropolarimetric observations of the solar atmosphere, wavelength variations of the emergent intensity and polarization translate into information on the depth…
Onset of penumbra formation
M. García-Rivas, J. Jurčák, N. Bello González +3
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…
Decay of a photospheric transient filament at the boundary of a pore and the chromospheric response
Philip Lindner, Rolf Schlichenmaier, Nazaret Bello González +1
Intermediate stages between pores and sunspots are a rare phenomenon and can manifest with the formation of transient photospheric penumbral-like filaments. Although the magnetic f…
Effects of solar evolution on finite acquisition time of Fabry-Perot-Interferometers in high resolution solar physics
Rolf Schlichenmaier, Daniel Pitters, Juan Manuel Borrero +1
The imaging spectro-polarimeter VTF (Visible Tunable Filter) will be operated at the Daniel K. Inouye Solar Telescope (DKIST). Due to its capability of resolving dynamic fine struc…
The European Solar Telescope
C. Quintero Noda, R. Schlichenmaier, L. R. Bellot Rubio +14
The European Solar Telescope (EST) is a project aimed at studying the magnetic connectivity of the solar atmosphere, from the deep photosphere to the upper chromosphere. Its design…
On the (in)stability of sunspots
Hanna Strecker, Wolfgang Schmidt, Rolf Schlichenmaier +1
The stability of sunspots is one of the long-standing unsolved puzzles in the field of solar magnetism. We study the effects that destabilise and stabilise the flux tube of a simul…
Characterization of the umbra-penumbra boundary by the vertical component of the magnetic field -- Analysis of ground-based data from the GREGOR Infrared Spectrograph
P. Lindner, R. Schlichenmaier, N. Bello González
The vertical component of the magnetic field () was found to reach a constant value at the umbra-penumbra boundary of stable sunspots in a recent statistical study of Hino…
A distinct magnetic property of the inner penumbral boundary III. Analysis of simulated sunspots
Jan Jurcak, Markus Schmassmann, Matthias Rempel +2
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 anal…
Science Requirement Document (SRD) for the European Solar Telescope (EST) (3rd Edition, December 2025)
Rolf Schlichenmaier, Luis R. Bellot Rubio, Manuel Collados Vera +31
The European Strategy Forum on Research Infrastructures (ESFRI) included the European Solar Telescope (EST) as an ESFRI Project in its 2016 Roadmap and confirmed this status in 202…
Convective blueshifts in the solar atmosphere: III. High-accuracy observations of spectral lines in the visible
Johannes Löhner-Böttcher, Wolfgang Schmidt, Rolf Schlichenmaier +2
Convective motions in the solar atmosphere cause spectral lines to become asymmetric and shifted in wavelength. For photospheric lines, this differential Doppler shift varies from…
Magnetic properties of a long-lived sunspot - Vertical magnetic field at the umbral boundary
Markus Schmassmann, Rolf Schlichenmaier, Nazaret Bello González
Context. In a recent statistical study of sunspots in 79 active regions, the vertical magnetic field component averaged along the umbral boundary is found to be inde…
Photospheric Magnetic Fields of the Trailing Sunspots in Active Region NOAA 12396
M. Verma, H. Balthasar, C. Denker +27
The solar magnetic field is responsible for all aspects of solar activity. Sunspots are the main manifestation of the ensuing solar activity. Combining high-resolution and synoptic…
Inference of magnetic fields in the very quiet Sun
M. J. Mart\' inez González, A. Pastor Yabar, A. Lagg +29
We present high-precision spectro-polarimetric data with high spatial resolution (0.4) of the very quiet Sun at 1.56m obtained with the GREGOR telescope to shed some light o…
Absolute velocity measurements in sunspot umbrae
J. Löhner-Böttcher, W. Schmidt, R. Schlichenmaier +3
In sunspot umbrae, convection is largely suppressed by the strong magnetic field. Previous measurements reported on negligible convective flows in umbral cores. Based on this, nume…
The magnetic nature of umbra-penumbra boundary in sunspots
Jan Jurčák, Reza Rezaei, Nazaret Bello González +2
Sunspots are the longest-known manifestation of solar activity, and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penu…
Penumbral thermal structure below the visible surface
J. M. Borrero, M. Franz, R. Schlichenmaier +2
. The thermal structure of the penumbra below its visible surface (i.e., ) has important implications for our present understanding of sunspots and their penumb…
A distinct magnetic property of the inner penumbral boundary. II. Formation of a penumbra at the expense of a pore
Jan Jurcak, Nazaret Bello Gonzalez, Rolf Schlichenmaier +1
We recently presented evidence that stable umbra-penumbra boundaries are characterised by a distinct canonical value of the vertical component of the magnetic field, $B^{\rm stable…
Three-dimensional structure of a sunspot light bridge
T. Felipe, M. Collados, E. Khomenko +26
Active regions are the most prominent manifestations of solar magnetic fields; their generation and dissipation are fundamental problems in solar physics. Light bridges are commonl…
Spectropolarimetric observations of an arch filament system with the GREGOR solar telescope
H. Balthasar, P. Gömöry, S. J. González Manrique +27
Arch filament systems occur in active sunspot groups, where a fibril structure connects areas of opposite magnetic polarity, in contrast to active region filaments that follow the…
Active region fine structure observed at 0.08 arcsec resolution
R. Schlichenmaier, O. von der Lühe, S. Hoch +19
The various mechanisms of magneto-convective energy transport determines the structure of sunspots and active regions. We characterise the appearance of light bridges and other fin…
Upper Chromospheric Magnetic Field of a Sunspot Penumbra: Observations of Fine Structure
J. Joshi, A. Lagg, S. K. Solanki +22
The fine-structure of magnetic field of a sunspot penumbra in the upper chromosphere is to be explored and compared to that in the photosphere. High spatial resolution spectropolar…
Horizontal flow fields in and around a small active region-- The transition period between flux emergence and decay
M. Verma, C. Denker, H. Balthasar +28
Aims. Combining high-resolution and synoptic observations aims to provide a comprehensive description of flux emergence at photospheric level and of the growth process that eventua…
Flows in and around active region NOAA12118 observed with the GREGOR solar telescope and SDO/HMI
M. Verma, C. Denker, H. Balthasar +28
Accurate measurements of magnetic and velocity fields in and around solar active regions are key to unlocking the mysteries of the formation and the decay of sunspots. High spatial…