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The lack of sources that generates intense THz pulses have in many years limited the field of THz science. Until recently intense THz pulses have been hard to generate using nonlinear crystals such as Lithium Niobate (LiNbO3) with high efficiency. In this thesis a method is presented for achieving short and intense THz pulses through optical rectification using the recently developed tilted pulsef
In this thesis, a method for producing few-cycle short wavelength infrared pulses is presented. The pulses are created by down converting the 800 nm output of a Ti:Sapphire laser in an optical parametric amplifier to 1300 nm, and spectrally broadened in a hollow core fiber in order to obtain a short transform limited pulse duration. Further, they are to be compressed using the anomalous dispersion
In this work, we numerically study a self-guiding process in which ionization plays a dominant role and analyze its effect on high-order harmonic generation (HHG) in gases. Although this type of self-guiding-termed "plasmacore- induced self-guiding" in previous works-limits the achievable cutoff by regulating the intensity of the laser beam, it provides favorable conditions for phase matching, whi
The Horizon 2020 project EuPRAXIA (European Plasma Research Accelerator with eXcellence In Applications) is producing a conceptual design report for a highly compact and cost-effective European facility with multi-GeV electron beams accelerated using plasmas. EuPRAXIA will be set up as a distributed Open Innovation platform with two construction sites, one with a focus on beam-driven plasma accele
It has been shown by Fano [1] that photoionization of a cesium atom by a laser pulse tuned to the vicinity of a Cooper minimum generates spin-polarized electrons. Here we show that while photoionization of rare gases does not provide large spin polarization in the vicinity of the Cooper minimum, the Fano resonances yield much higher overall spin polarization (≥40%). The spin polarization increases
This thesis develops a locally deployed LLM-assisted system for automating CFD simulations from natural-language physical modelling tasks, including OpenFOAM case setup generation, solver execution, error diagnosis, and iterative correction. Unlike many recent LLM-driven CFD agents that mainly rely on frontier cloud models, this work investigates whether open-weight local LLMs with stronger data p
Popular Abstract in Swedish Dagens samhälle är väldigt beroende av fordon av olika slag. Aldrig förr har människor rest till olika delar av världen, så mycket som idag. Den enorma mängden resors och transporter som sker varje dag är en tung belastning för vår natur. Bilar och lastbilar, som ökar i antal varje dag, släpper ut giftiga avgaser på vägarna och flygplan förbrukar enorma mängder fossilt Urban traffic involves frequent acceleration and deceleration. During deceleration, the energy previously used to accelerate the vehicle is mainly wasted on heat generated by the friction brakes. If this energy that is wasted in traditional internal combustion engines (ICE) could be saved, the fuel economy would improve. Today there are several solutions to meet the demand for better fuel economy
Energisystemet genomgår en förändring mot fossilfrihet där värme är en stor och viktig aspekt. Fjärrvärmesystemet är grunden för värmeleveranser i Sverige. 60 % av svenska hushåll har fjärrvärme som värmekälla. Fjärrvärmesystemets utveckling präglas av ett mer sammankopplat system där allt fler parter samverkar, inklusive slutkunderna. Denna studie har undersökt kundbaserad värmeflexibilitet som eThe energy system is undergoing a transition toward fossil-free operation, in which heating is a major and important aspect. The district heating system forms the basis for heat supply in Sweden, with 60 % of Swedish households using district heating as their main heat source. The development of the district heating system is characterized by increasing interconnections and collaberations. This cr
Popular Abstract in Swedish I avhandlingen presenteras delar till radiomottagare med extremt låg effektförbrukning. Detta behövs då dagens samhälle blir allt mer och mer uppkopplat, och detta gäller inte bara persondatorer och mobiltelefoner. Med den snabba teknikutvecklingen inom radiokommunikation, driven av små och smarta mobiltelefoner, går det nu även att få prylar av alla de slag att tala meHistorically, research on radio communication has focused on improving range and data rate. In the last decade, however, there has been an increasing demand for low power and low cost radios that can provide connectivity with small devices around us. They should be able to offer basic connectivity with a power consumption low enough to function extended periods of time on a single battery charge,
The world of information is literally at one’s fingertips, allowing access to previously unimaginable amounts of data, thanks to advances in wireless communication. The growing demand for high speed data has necessitated theuse of wider bandwidths, and wireless technologies such as Multiple-InputMultiple-Output (MIMO) have been adopted to increase spectral efficiency.These advanced communication t
The World Trade Organization’s Dispute Settlement Mechanism is exclusively focused on trade; however, there is a potential for it to be utilized to address environmental problems that are also trade distorting. One area where trade and environmental concerns overlap is fossil fuel subsidies. Fossil fuel subsidies support an incumbent energy regime against new renewable alternatives but also benefi
This thesis presents experimental results on the development and optimization of novel and highly compact sources of beams of fast ions, relativistic electrons and coherent x-rays, driven by intense laser-plasma interactions. The rapid development of high-power, short-pulse laser systems have made available peak powers reaching the petawatt regime and focused intensities reaching 10^21 W/cm2. Whe
Vid avdelningen för kärnfysik utvecklas för närvarande andra generationens Ir-koincidensspektrometer. Anledningen till detta är att det finns ett stort behov bland geologer att mäta spårkvantiteter av Iridium i olika geologiska skikt för att korrelera skiktens ålder med eventuella stora meteoritnedslag. Första generationens spektrometer byggde på en dubbelkoincidens mätt med två HPGe-detektorer, mPresently, the development of the second generation Ir coincidence spectrometer is talking place at the division of Nuclear Physics. There is a large need among geologists to measure trace quantities of Ir in different geological layers and correlate the age of the layer with different large meteorite impacts. The first generation Ir spectrometer was based on a coincidence measured by two HPGe det
Microchannels are widely used for heat transfer enhancement. The pressure characteristics are one of the most important factors affecting the heat transfer performance, and the pressure regulation may also control the heat transfer precisely in turn. As a common flow pattern of two-phase flow, slug flow has obvious advantages for heat and mass transfer, like steady flow rate and large interface ar
In this work we report the impact of using mid-infrared laser-induced thermal grating spectroscopy (IRLITGS) for temperature measurements in flames by probing hot water lines. The measurements have been performed in the product zone of laminar atmospheric CH 4 /H 2 /air flat flames with equivalence ratio ranging between 0.6 and 1.05. LITGS is a technique based on thermalization through collisions
We describe a series of microcalorimeter X-ray spectrometers designed for a broad suite of measurement applications. The chief advantage of this type of spectrometer is that it can be orders of magnitude more efficient at collecting X-rays than more traditional high-resolution spectrometers that rely on wavelength-dispersive techniques. This advantage is most useful in applications that are tradit
Annual social insects are an integral functional group of organisms, particularly in temperate environments. An emblematic part of their annual cycle is the social phase, during which the colony-founding queen rears workers that later assist her in rearing sexual progeny (gynes and drones). In many annual social insects, such as species of bees, wasps, and other groups, developing larvae are provi
The modification of the electronic properties of CeO2 thin films through Cu doping is a promising approach to enhancing their performance in photoinduced water splitting (WS). In this study, undoped and Cu-doped CeO2 films of 5 nm thickness with 5 and 11% Cu atomic concentrations were characterized under ambient pressure conditions by near-edge X-ray absorption fine structure (NEXAFS) to provide i
LUMES 2020-2022 Thesis Seminar Schedule 23-25 MAY 2022 MONDAY 23 May 2022 Day Venue Examiner Respondent Thesis Title Discussants Supervisor 8.00-8.45 Vandana Anne Jerneck Ludwig B. Sonesson Beyond the Fossil Era: Transformative Pedagogy for Sustainability Wanyi Ji Elina Andersson 9.00-9.45 Vandana Anne Jerneck Anna Elfström Falling between the chairs or too many chairs to fall on? A Narrative Poli
Testing ofIntegrated Circuits is important to ensure the production offault-free chips. However, testing is becoming cumbersome andexpensive due to the increasing complexity of these ICs. Technologydevelopment has made it possible to produce chips where a completesystem, with an enormous transistor count, operating at a highclock frequency, is placed on a single die - SOC (System-on-Chip).The devi
