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 spectra...

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Detalles Bibliográficos
Autores: Balthasar, H., Gömöry, P., González Manrique, S. J., Kuckein, C., Kavka, J., Kučera, A., Schwartz, P., Vašková, R., Berkefeld, T., Collados Vera, M., Denker, C., Feller, A., Hofmann, A., Lagg, A., Nicklas, H., Orozco Suárez, David, Pastor Yabar, A., Rezaei, R., Schlichenmaier, R., Schmidt, D., Schmidt, W., Sigwarth, M., Sobotka, M., Solanki, S. K., Soltau, D., Staude, J., Strassmeier, K. G., Volkmer, R., von der Lühe, O., Waldmann, T.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2016
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/395793
Acceso en línea:http://hdl.handle.net/10261/395793
Access Level:acceso abierto
Palabra clave:Sun: filaments
Sun: photosphere
Techniques: polarimetric
Techniques: spectroscopic
Descripción
Sumario: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 λ 1082.7 nm, He I λ 1083.0 nm, and Ca I λ 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–1 in the chromospheric helium line. Our findings can be explained with new emerging flux where the matter flows downward along the field lines of rising flux tubes, in agreement with earlier results. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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