Übungen zur Vorlesung Theoretische Physik III: Elektrodynamik/Computergestützte Elektrodynamik im Wintersemester 2004/05 für den Studiengang Physik und den Bakkalaureusstudiengang Computational Science

Some experiments have indicated the possible existence of par ticles with a negative inertial mass. It is shown under which condit ions Weber’s electrodynamics gives rise to this effect. Some specific experiments related to this aspect of Weber’s law are described. Two particles equ ally electrified with charges of the same sign would then move toward one an other if they had negative effective inertial masses. A new concept for nuclear fusion is presented based on the possibility of creating a negative effective inertial mass for ions. It is then considered some properties of the inertial dipole, that is, a system composed by a pair of particles in which one particle has a positive effective inertial mass while the other particle has a negative effective inertial mass. The possible utilization of the inertialdipole as a propulsion system is briefly discussed.

Die Arbeit untersucht theoretisch die Wechselwirkung neutraler Teilchen (Atome, Moleküle) mit Oberflächen, soweit sie durch das elektromagnetische Feld vermittelt wird. Spektrale Energiedichten und Kohärenzfunktionen werden hergeleitet und liefern eine umfassende Charakterisierung des Felds auf der sub-Wellenlängen-Skala. Die Ergebnisse finden auf zwei Teilgebieten Anwendung: in der integrierten Atomoptik, wo ultrakalte Atome an thermische Oberflächen koppeln, und in der Nahfeldoptik, wo eine Auflösung unterhalb der Beugungsbegrenzung mit einzelnen Molekülen als Sonden und Detektoren erzielt werden kann. / We theoretically discuss the interaction of neutral particles (atoms, molecules) with surfaces in the regime where it is mediated by the electromagnetic field. A thorough characterization of the field at sub-wavelength distances is worked out, including energy density spectra and coherence functions. The results are applied to typical situations in integrated atom optics, where ultracold atoms are coupled to a thermal surface, and to single molecule probes in near field optics, where sub-wavelength resolution can be achieved.

Electric breakdown in power transformers is preceded by pre-breakdown events such as streamers. The understanding of these phenomena is important in order to optimize liquid insulation systems. Earlier works have derived a model that describes streamers in transformer oil and utilized a finite element method to produce numerical solutions. This research investigates the consequences of changing the numerical method to a finite volume-based solver implemented in OpenFOAM. Using a standardized needle-sphere geometry, a number of oil and voltage combinations were simulated, and the results are for the most part similar to those produced by the previous method. In cases with differing results the change is attributed to the more stable numerical performance of the OpenFOAM solver. A proof of concept for the extension of the simulation from a two-dimensional axial symmetry to three dimensions is also presented. / Elektriska genomslag i högspänningstransformatorer föregås av bildandet av elektriskt ledande kanaler som kallas streamers. En god förståelse av detta fenomen är viktigt vid konstruktionen av oljebaserad elektrisk isolation. Tidigare forskning i ämnet har tagit fram en modell för fortplantningen av streamers. Denna modell har sedan lösts numeriskt av ett beräkningsverktyg baserat på finita elementmetoden. I denna uppsats undersöks konsekvenserna av att byta metod till finita volymsmetoden genom att implementera en lösare i OpenFOAM. En standardiserad nål-sfär-geometri har ställts upp och ett flertal kombinationer av oljor och spänningar har simulerats. De flesta resultaten visar god överensstämmande med tidigare forskning medan resultat som avviker har tillskrivits de goda numeriska egenskaperna hos OpenFOAM-lösaren. En ny typ av simulering har även genomförts där simulationen utökas från en tvådimensionell axisymmetrisk geometri til tre dimensioner.

The discourse presented here is aimed at examining the justification of applications of current analysis to real world problems.

Some experiments have indicated the possible existence of par ticles with a negative inertial mass. It is shown under which condit ions Weber’s electrodynamics gives rise to this effect. Some specific experiments related to this aspect of Weber’s law are described. Two particles equ ally electrified with charges of the same sign would then move toward one an other if they had negative effective inertial masses. A new concept for nuclear fusion is presented based on the possibility of creating a negative effective inertial mass for ions. It is then considered some properties of the inertial dipole, that is, a system composed by a pair of particles in which one particle has a positive effective inertial mass while the other particle has a negative effective inertial mass. The possible utilization of the inertialdipole as a propulsion system is briefly discussed.

The ionospheric variability and its complexity is strongly dependent on continuous varying intense solar extreme ultraviolet (EUV) and UV radiations. We investigate the ionospheric response to the solar activity variations during the solar cycle (SC) 23 (1999-2008) and 24 (2009-2017) by using the F10.7 index, and Total Electron Content (TEC) maps provided by the international GNSS service (IGS). Wavelet cross-correlation method is used to evaluate the correlation between F10.7 and the global mean TEC. The maximum correlation is observed at the solar rotation time scale (16-32 days). There is a significant difference in the correlation at the time scale of 32-64 days. During SC 23, the correlation is stronger than during SC 24. This is probably due to the longer lifetime of active regions during SC 23. The wavelet variance estimation method suggests that the variance during SC 23 is more significant than during SC 24. Furthermore, the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) model was used to reproduce the ionospheric delay of about 1-2 days observed in the IGS TEC observations. A strong correlation was modelled as well as observed during a high solar activity year (2013) as compared to low a solar activity year (2008). / Die ionosphärische Variabilität ist stark abhängig von der kontinuierlich variierenden intensiven solaren extrem ultravioletten (EUV) und UV-Strahlung. Wir untersuchen die ionosphärische Reaktion auf Variationen der Sonnenaktivität während der Sonnenzyklen (SC) 23 (1999-2008) und 24 (2009-2017) mit Hilfe des F10.7-Radioflussindexes und TEC (Gesamtelektronengehalt, Total Electron Content) -Karten, die vom internationalen GNSS-Dienst (IGS) bereitgestellt werden. Wavelet-Kreuzkorrelation wird verwendet, um die Korrelation zwischen F10.7 und global gemitteltem TEC zu bestimmen. Die maximale Korrelation wird auf der Zeitskala der Sonnenrotation (16-32 Tage) beobachtet. Es gibt einen signifikanten Unterschied in der Korrelation auf der Zeitskala von 32 bis 64 Tagen. Während des SC 23 ist die Korrelation stärker als während SC 24. Dies ist auf die längere Lebensdauer der aktiven Regionen zurückzuführen. Das Wavelet-Varianz-Schätzverfahren legt nahe, dass die Varianz beim SC 23 mehr von Bedeutung ist, als während SC 24. Des Weiteren wurde das gekoppelte Thermosphäre-Ionosphäre-Plasmasphäre-Elektrodynamik (CTIPe) Modell verwendet, um die ionosphärische Verzögerung von 1-2 Tagen zu reproduzieren. Eine starke Korrelation wurde bei hoher Sonnenaktivität (2013) im Gegensatz zu geringer Sonnenaktivität (2008) simuliert und auch beobachtet.

The Planck constant is one of the most important constants in nature, as it describes the world governed by quantum mechanics. However, it cannot be derived from other natural constants. We present a model from which it is possible to derive this constant without any free parameters. This is done utilizing the force between two oscillating electric dipoles described by an extension of Weber electrodynamics, based on a gravitational model by Assis. This leads not only to gravitational forces between the particles but also to a newly found Casimir-type attraction. We can use these forces to calculate the maximum point mass of this model which is equal to the Planck mass and derive the quantum of action. The result hints to a connection of quantum effects like the Casimir force and the Planck constant with gravitational ones and the origin of mass itself.

Topological insulators are materials with their electronic band structure in bulk resembling that of an ordinary insulator, but the surface states are metallic. These surface states are topologically protected, meaning that they are robust against impurities. The topological phenomena of three dimensional topological insulators can be expressed within topological field theories, predicting axion electrodynamics and the topological magnetoelectric effect. An experiment have been suggested to measure the topological phenomena. In this thesis, the underlying theory and details around the experiment are explained and more detailed derivations and expressions are provided.

The discourse presented here is aimed at examining the justification of applications of current analysis to real world problems.