Evolutionary tracks of quiet-Sun magnetic features
This thesis presents a study of quiet-Sun magnetic features in the solar photosphere. Magnetic fields in the quiet Sun organize on small spatial scales, evolve very rapidly, and produce weak polarization signals. With these properties their observation requires high spatial and temporal resolution t...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/149465 |
| Acceso en línea: | http://hdl.handle.net/10261/149465 |
| Access Level: | acceso abierto |
| Palabra clave: | Sol Campo magnético solar Espectropolarimetría astrofísica Imaging Magnetograph eXperiment (IMAX) |
| Sumario: | This thesis presents a study of quiet-Sun magnetic features in the solar photosphere. Magnetic fields in the quiet Sun organize on small spatial scales, evolve very rapidly, and produce weak polarization signals. With these properties their observation requires high spatial and temporal resolution together with sensitive and accurate polarimetric measurements. It is for these instrumental limitations that the origin and evolution of these features remains elusive. The Imaging Magnetograph eXperiment (IMaX) is an imaging spectropolarimeter that flew over the Artic Circle aboard the SUNRISE balloon-borne stratospheric mission. IMaX was designed to mitigate the above mentioned issues and has provided polarimetric observations with unprecedentedly high spatial resolution of a hundred kilometers. Flying in the stratosphere, it obtained stable, nearly seeing-free time series, and its imaging capabilities allowed to cover large areas of the Sun simultaneously. All these features are indeed crucial when studying the highly dynamic nature of the quiet-Sun magnetism. The thesis gathers empirical evidence of magnetoconvection at the smallest scales ever observed. The evolutionary tracks of several different quiet-Sun magnetic structures in a continuous interaction with photospheric convection are presented. Specifically, we study 1) the formation and evolution of an isolated magnetic element; 2) the dynamics of multicore magnetic structures; and 3) the relation between magnetic features and convectively driven, long living sinks at the junctions of several mesogranular cells. Seen at a scale of one hundred kilometers, we find that the evolution of an isolated quiet- Sun magnetic element is a complex process where many phenomena are involved. The formation starts when a small-scale magnetic loop emerges through the solar surface in a granular upflow. Its footpoints are soon swept to nearby intergranular lanes where some, weak positive polarity patches are already present. |
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