{"id":{"repo_id":"freiburg-diss","oai_identifier":"oai:freidok.uni-freiburg.de:2346"},"canonical_url":"https://search.dev.ndltd.org/etd/freiburg-diss/oai:freidok.uni-freiburg.de:2346","repository":{"repo_id":"freiburg-diss","name":"University of Freiburg","base_url":"https://freidok.uni-freiburg.de/oai/oai2.php"},"display":{"title":"The 3-D topology of magnetic fields in and around sunspots","abstract":"The most prominent features on the surface of the solar disc are the sunspots, which have been studied since their detection in the 17th century. Despite this years and centuries of scientific investigations, surprisingly many facets of sunspots are not well understood. In this thesis, the properties of a sunspots' penumbra are derived from the observed spectra by means of an inversion, a forward modeling technique. A method for the construction of a 3-dimensional model of the field topology from the inversion results is presented. It offers the possibility to build a toy-model of the spot. This allows to investigate the relationships between the geometry and other properties of the sunspot like flow velocities, intensity, temperature, or field strength. The application of the procedure to time series of observations will allow to study the temporal evolution of the geometry and the other properties, to determine the physical processes happening and their respective drivers.
A second part of the thesis is devoted to the analysis of isolated field concentrations in the surroundings of the sunspot. These isolated magnetic elements are assumed to be the elementary building blocks of the solar surface magnetism. In the turbulent surroundings of the solar atmosphere, only relatively strong concentrations with a field strength above 1 kG are assumed to be stable at all. Such field concentrations produce brightenings in the G band, where a lot of spectral lines of the CH molecule are present. Inside magnetic fields, the density is reduced, as the magnetic pressure contributes to the pressure balance equation. Thus, the reduced density allows to see to deeper layers of the atmosphere with higher temperature. If the CH-molecules dissociate due to the higher temperature, the spectral lines disappear and the intensity increases strongly. Due to the small size of the field concentration, the brightenings are strongly localized (G-band Bright Points''). In this study, we find a much larger variability of the Bright Point properties than expected, which puts their elementary nature in some doubt.
In the conclusions of this work, the resulting 3-D topology of the sunspot is used in an attempt to develop a consistent picture of the development and the fine structure of sunspots.","abstract_html":"The most prominent features on the surface of the solar disc are the sunspots, which have been studied since their detection in the 17th century. Despite this years and centuries of scientific investigations, surprisingly many facets of sunspots are not well understood. In this thesis, the properties of a sunspots' penumbra are derived from the observed spectra by means of an inversion, a forward modeling technique. A method for the construction of a 3-dimensional model of the field topology from the inversion results is presented. It offers the possibility to build a toy-model of the spot. This allows to investigate the relationships between the geometry and other properties of the sunspot like flow velocities, intensity, temperature, or field strength. The application of the procedure to time series of observations will allow to study the temporal evolution of the geometry and the other properties, to determine the physical processes happening and their respective drivers. <br> <br>A second part of the thesis is devoted to the analysis of isolated field concentrations in the surroundings of the sunspot. These isolated magnetic elements are assumed to be the elementary building blocks of the solar surface magnetism. In the turbulent surroundings of the solar atmosphere, only relatively strong concentrations with a field strength above 1 kG are assumed to be stable at all. Such field concentrations produce brightenings in the G band, where a lot of spectral lines of the CH molecule are present. Inside magnetic fields, the density is reduced, as the magnetic pressure contributes to the pressure balance equation. Thus, the reduced density allows to see to deeper layers of the atmosphere with higher temperature. If the CH-molecules dissociate due to the higher temperature, the spectral lines disappear and the intensity increases strongly. Due to the small size of the field concentration, the brightenings are strongly localized (G-band Bright Points''). In this study, we find a much larger variability of the Bright Point properties than expected, which puts their elementary nature in some doubt. <br> <br>In the conclusions of this work, the resulting 3-D topology of the sunspot is used in an attempt to develop a consistent picture of the development and the fine structure of sunspots.","abstract_has_math":false,"creators":["Beck, Christoph F."],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Schmidt, Wolfgang"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T02:22:46Z","subjects":["Photosphaere","photosphere"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://freidok.uni-freiburg.de/data/2346","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Schmidt, Wolfgang"]},{"key":"dc:creator","label":"Author","values":["Beck, Christoph F."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["DoctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Photosphaere","photosphere"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The most prominent features on the surface of the solar disc are the sunspots, which have been studied since their detection in the 17th century. Despite this years and centuries of scientific investigations, surprisingly many facets of sunspots are not well understood. In this thesis, the properties of a sunspots' penumbra are derived from the observed spectra by means of an inversion, a forward modeling technique. A method for the construction of a 3-dimensional model of the field topology from the inversion results is presented. It offers the possibility to build a toy-model of the spot. This allows to investigate the relationships between the geometry and other properties of the sunspot like flow velocities, intensity, temperature, or field strength. The application of the procedure to time series of observations will allow to study the temporal evolution of the geometry and the other properties, to determine the physical processes happening and their respective drivers.
A second part of the thesis is devoted to the analysis of isolated field concentrations in the surroundings of the sunspot. These isolated magnetic elements are assumed to be the elementary building blocks of the solar surface magnetism. In the turbulent surroundings of the solar atmosphere, only relatively strong concentrations with a field strength above 1 kG are assumed to be stable at all. Such field concentrations produce brightenings in the G band, where a lot of spectral lines of the CH molecule are present. Inside magnetic fields, the density is reduced, as the magnetic pressure contributes to the pressure balance equation. Thus, the reduced density allows to see to deeper layers of the atmosphere with higher temperature. If the CH-molecules dissociate due to the higher temperature, the spectral lines disappear and the intensity increases strongly. Due to the small size of the field concentration, the brightenings are strongly localized (G-band Bright Points''). In this study, we find a much larger variability of the Bright Point properties than expected, which puts their elementary nature in some doubt.
In the conclusions of this work, the resulting 3-D topology of the sunspot is used in an attempt to develop a consistent picture of the development and the fine structure of sunspots.","Die hervorstechendsten Erscheinungen auf der Oberfläche der Sonne sind die Sonnenflecken, die seit ihrer Entdeckung im 17. Jahrhundert untersucht wurden. Trotz dieser Jahre und Jahrhunderte wissenschaftlicher Untersuchungen sind überraschend viele ihrer Facetten nicht wohl verstanden. In dieser Doktorarbeit werden die Eigenschaften der Penumbra eines Sonnenfleckes aus den beobachteten Spektren durch eine Inversion, eine Vorwärts-modellierung der solaren Atmosphäre, abgeleitet. Eine Methode für die Konstruktion eines 3-dimensionalen Modells aus den Inversionsergebnissen wird beschrieben. Sie bietet die Möglichkeit, ein Spielzeug-Modell des Fleckes zu erstellen. Dieses kann dazu benutzt werden, die Zusammenhänge zwischen der Geometrie und anderen Eigenschaften des Sonnenfleckes wie Strömungsgeschwindigkeit, Intensität, Temperatur oder Feldstärke zu untersuchen. Die Anwendung des Verfahrens auf Zeitreihen von Beobachtungen erlaubt es, die zeitliche Entwicklung der Geometrie und der anderen Eigenschaften zu studieren, um die ablaufenden physikalischen Prozesse und ihre treibenden Kräfte zu finden.
Ein zweiter Teil der Arbeit ist der Analyse von Feldkonzentrationen in der Umgebung des Sonnenfleckes gewidmet. Diese magnetischen Elemente sollen die elementaren Bausteine des Magnetismus auf der Sonnenoberfläche sein. In der turbulenten Sonnenatmosphäre sind nur verhältnismässig starke Konzentrationen mit einer Feldstärke von über einem kG stabil. Solche Feldkonzentrationen führen zu Aufhellungen im G-Band, in dem eine grosse Anzahl von Spektrallinien des CH-Moleküls vorhanden ist. Innerhalb der magnetischen Felder ist die Dichte verringert, da der magnetische Druck zum Druckgleichgewicht beiträgt. Die verringerte Dichte erlaubt es aber, bis zu tieferen Schichten der Atmosphäre mit höherer Temperatur zu sehen. Wenn die CH-Moleküle wegen der höheren Temperatur dissoziieren, verschwinden die Spektrallinien und die Intensität erhöht sich stark. Wegen der kleinen Ausmaße der Feldkonzentrationen werden die Aufhellungen G-band Bright Points'' genannt. In dieser Studie finden wir eine viel größere Variation in den Eigenschaften der Bright Points als erwartet, was ihre elementare Natur in Zweifel setzt.
In der Zusammenfassung dieser Arbeit wird die sich ergebende 3-D-Topologie des Sonnenflecks verwendet, um ein konsistentes Bild der Entwicklung und der Feinstruktur von Sonnenflecken zu entwerfen."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The 3-D topology of magnetic fields in and around sunspots","Die 3-dimensionale Topologie von Magnetfeldern in Sonnenflecken und ihrer Umgebung"]}]}],"canonical_facts":{"dc:contributor":["Schmidt, Wolfgang"],"dc:creator":["Beck, Christoph F."],"dc:description.abstract":["The most prominent features on the surface of the solar disc are the sunspots, which have been studied since their detection in the 17th century. Despite this years and centuries of scientific investigations, surprisingly many facets of sunspots are not well understood. In this thesis, the properties of a sunspots' penumbra are derived from the observed spectra by means of an inversion, a forward modeling technique. A method for the construction of a 3-dimensional model of the field topology from the inversion results is presented. It offers the possibility to build a toy-model of the spot. This allows to investigate the relationships between the geometry and other properties of the sunspot like flow velocities, intensity, temperature, or field strength. The application of the procedure to time series of observations will allow to study the temporal evolution of the geometry and the other properties, to determine the physical processes happening and their respective drivers.
A second part of the thesis is devoted to the analysis of isolated field concentrations in the surroundings of the sunspot. These isolated magnetic elements are assumed to be the elementary building blocks of the solar surface magnetism. In the turbulent surroundings of the solar atmosphere, only relatively strong concentrations with a field strength above 1 kG are assumed to be stable at all. Such field concentrations produce brightenings in the G band, where a lot of spectral lines of the CH molecule are present. Inside magnetic fields, the density is reduced, as the magnetic pressure contributes to the pressure balance equation. Thus, the reduced density allows to see to deeper layers of the atmosphere with higher temperature. If the CH-molecules dissociate due to the higher temperature, the spectral lines disappear and the intensity increases strongly. Due to the small size of the field concentration, the brightenings are strongly localized (G-band Bright Points''). In this study, we find a much larger variability of the Bright Point properties than expected, which puts their elementary nature in some doubt.
In the conclusions of this work, the resulting 3-D topology of the sunspot is used in an attempt to develop a consistent picture of the development and the fine structure of sunspots.","Die hervorstechendsten Erscheinungen auf der Oberfläche der Sonne sind die Sonnenflecken, die seit ihrer Entdeckung im 17. Jahrhundert untersucht wurden. Trotz dieser Jahre und Jahrhunderte wissenschaftlicher Untersuchungen sind überraschend viele ihrer Facetten nicht wohl verstanden. In dieser Doktorarbeit werden die Eigenschaften der Penumbra eines Sonnenfleckes aus den beobachteten Spektren durch eine Inversion, eine Vorwärts-modellierung der solaren Atmosphäre, abgeleitet. Eine Methode für die Konstruktion eines 3-dimensionalen Modells aus den Inversionsergebnissen wird beschrieben. Sie bietet die Möglichkeit, ein Spielzeug-Modell des Fleckes zu erstellen. Dieses kann dazu benutzt werden, die Zusammenhänge zwischen der Geometrie und anderen Eigenschaften des Sonnenfleckes wie Strömungsgeschwindigkeit, Intensität, Temperatur oder Feldstärke zu untersuchen. Die Anwendung des Verfahrens auf Zeitreihen von Beobachtungen erlaubt es, die zeitliche Entwicklung der Geometrie und der anderen Eigenschaften zu studieren, um die ablaufenden physikalischen Prozesse und ihre treibenden Kräfte zu finden.
Ein zweiter Teil der Arbeit ist der Analyse von Feldkonzentrationen in der Umgebung des Sonnenfleckes gewidmet. Diese magnetischen Elemente sollen die elementaren Bausteine des Magnetismus auf der Sonnenoberfläche sein. In der turbulenten Sonnenatmosphäre sind nur verhältnismässig starke Konzentrationen mit einer Feldstärke von über einem kG stabil. Solche Feldkonzentrationen führen zu Aufhellungen im G-Band, in dem eine grosse Anzahl von Spektrallinien des CH-Moleküls vorhanden ist. Innerhalb der magnetischen Felder ist die Dichte verringert, da der magnetische Druck zum Druckgleichgewicht beiträgt. Die verringerte Dichte erlaubt es aber, bis zu tieferen Schichten der Atmosphäre mit höherer Temperatur zu sehen. Wenn die CH-Moleküle wegen der höheren Temperatur dissoziieren, verschwinden die Spektrallinien und die Intensität erhöht sich stark. Wegen der kleinen Ausmaße der Feldkonzentrationen werden die Aufhellungen G-band Bright Points'' genannt. In dieser Studie finden wir eine viel größere Variation in den Eigenschaften der Bright Points als erwartet, was ihre elementare Natur in Zweifel setzt.
In der Zusammenfassung dieser Arbeit wird die sich ergebende 3-D-Topologie des Sonnenflecks verwendet, um ein konsistentes Bild der Entwicklung und der Feinstruktur von Sonnenflecken zu entwerfen."],"dc:format.medium":["application/pdf"],"dc:subject":["Photosphaere","photosphere"],"dc:title":["The 3-D topology of magnetic fields in and around sunspots","Die 3-dimensionale Topologie von Magnetfeldern in Sonnenflecken und ihrer Umgebung"],"dc:type":["DoctoralThesis"]},"updated_at":"2026-07-24T02:22:46Z"}