16 research outputs found
Spectropolarimetric observations of an arch filament system with the GREGOR solar telescope
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 polarity inversion line. We used the GREGOR
Infrared Spectrograph (GRIS) to obtain the full Stokes vector in the spectral
lines Si I 1082.7 nm, He I 1083.0 nm, and Ca I 1083.9 nm. We focus on the
near-infrared calcium line to investigate the photospheric magnetic field and
velocities, and use the line core intensities and velocities of the helium line
to study the chromospheric plasma. The individual fibrils of the arch filament
system connect the sunspot with patches of magnetic polarity opposite to that
of the spot. These patches do not necessarily coincide with pores, where the
magnetic field is strongest. Instead, areas are preferred not far from the
polarity inversion line. These areas exhibit photospheric downflows of moderate
velocity, but significantly higher downflows of up to 30 km/s in the
chromospheric helium line. Our findings can be explained with new emerging flux
where the matter flows downward along the fieldlines of rising flux tubes, in
agreement with earlier results.Comment: Proceedings 12th Potsdam Thinkshop to appear in Astronomische
Nachrichte
Biological and molecular characterization of Prunus necrotic ringspot virus isolates from three rose cultivars
Molecular characterization of Prune dwarf virus cherry isolates from Slovakia shows their substantial variability and reveals recombination events in PDV RNA3
Molecular characterization of Prune dwarf virus cherry isolates from Slovakia shows their substantial variability and reveals recombination events in PDV RNA