Browsing Fakultät für Physik (inkl. GAUSS) by Referee "Niemeyer, Jens Prof. Dr."
Now showing items 1-15 of 15
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A search for the Rieger-type periodicity on the Sun- like stars
(2023-10-06)Solar activity undergoes variations over many different timescales. The main periodicity is 11 years, called Schwabe cycle. In addition to the 11-year cycle, shorter periodic variations known as Rieger cycles have been ... -
Simulations of Cosmological Structure Formation with Nonrelativistic Scalar Fields
(2023-01-20)Nonrelativistic, self-gravitating scalar fields are of current interest in several scenarios of cosmological structure formation. This includes the gravitational clustering of dark matter in the late-time Universe which ... -
Axion Miniclusters: Formation, Structure and Observational Signatures
(2022-09-29)The axion is one of the leading candidates for cosmological dark matter. It arises as the pseudo-Goldstone boson of a spontaneously broken global U(1) symmetry. If this symmetry is broken after inflation, cosmic string ... -
Experimental Investigation of Micrometric Droplets and Artificial Particles
(2022-04-28)Clouds and atmospheric particles (e.g. ice crystals, smoke, dust or pollen) heavily influence Earth's energy budget and contribute to the largest uncertainties in climate prediction models. Their treatment involves a huge ... -
Simulations of Bosonic Dark Matter
(2021-11-05)Dark matter is a hypothetical form of matter, which is thought to make up nearly $27\%$ of the contents in our Universe. An increasingly popular idea is that the dark matter could be composed of light (pseudo-)scalar ... -
Experimental investigation of a sheared thermally unstable boundary layer
(2021-07-02)In many natural and industrial systems, heat is transported by mixed convection, where an externally driven flow causes advection of the temperature field in addition to the fluid motion due to buoyancy of differentially ... -
Galaxy Formation With Ultralight Bosonic Dark Matter
(2020-05-18)Ultralight bosonic particles forming a coherent state are dark matter candidates with distinctive wave-like behaviour on the scale of dwarf galaxies and below. In this thesis, a new simulation technique for ultralight ... -
Structure Formation with Ultralight Axion Dark Matter
(2019-09-23)Ultralight axion is a scalar field with an extremely small mass $\sim10^{-22} eV$. It is proposed as an alternative dark matter candidate to the standard cold dark matter (CDM). If self-interactions between axions can be ... -
Simulating Structure Formation with Ultra-light Bosonic Dark Matter
(2019-01-16)Despite being a cornerstone of the standard model of cosmology, the exact nature of dark matter (DM) remains unknown. The lack of evidence for weakly interacting massive particles that could constitute DM is generating ... -
Slender Ca II H fibrils observed by SUNRISE/SuFI
(2018-04-24)This thesis is devoted to analyzing the morphological and oscillatory properties of slender \caiih{} fibrils (SCFs) in the lower solar chromosphere. The aim of this study is to deepen our understanding of the physical ... -
Modelling turbulent effects of stellar feedback in cosmological simulations
(2017-10-30)In order to study the influence of turbulence on star formation, stellar feedback, and the mixing of metals into the circumgalactic medium (CGM), we implemented a model for star formation and stellar feedback and employ ... -
Sub-grid Scale Modelling of Compressible Magnetohydrodynamic Turbulence: Derivation and A Priori Analysis
(2015-12-11)Turbulence is one of the oldest and trickiest unsolved problems in our understanding of the universe. The addition of magnetic fields increases its complexity exorbitantly. There are numerous astrophysical examples where ... -
Fully kinetic PiC simulations of current sheet instabilities for the Solar corona
(2015-10-20)The plasma of the Solar corona is practically collisionless. This imposes an important role of waves and micro-turbulent interactions with particles for plasma transport, dissipation, stability, etc, since binary particles ... -
The Influence of Small-Scale Anisotropies and the Large-Scale Environment on the Observed Properties of Lyman-Alpha Emitters
(2014-12-15)Lyman-alpha emitters have become an important tool for the study of star formation, galaxy formation and galaxy evolution. However, the non-linear radiative transport of Lyman-alpha radiation remains a puzzling problem. ... -
The response of the corona to different spatial distributions of heat input
(2014-04-09)Explaining the existence of the million degree corona on top of the much cooler Solar surface has provided scientist with a challenge for a several decades. It is not possible for a cooler object to heat something that ...