Sökning: "energy cascade"

Visar resultat 16 - 20 av 81 avhandlingar innehållade orden energy cascade.

  1. 16. Statistical characteristics of two-dimensional and quasigeostrophic turbulence

    Författare :Andreas Vallgren; Erik Lindborg; Johan Nilsson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; two-dimensional turbulence; decaying turbulence; quasigeostrophic turbulence; direct numerical simulation DNS ; coherent vortices; energy cas- cade; enstrophy cascade; intermittency; massively parallel simulations; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos;

    Sammanfattning : Two codes have been developed and implemented for use on massively parallelsuper computers to simulate two-dimensional and quasigeostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. LÄS MER

  3. 17. Quantitative Modeling of Gain in Quantum Cascade Lasers under Operational Intensities

    Författare :David Winge; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; non-linear response; quantum cascade lasers; modelling; Non-equilibrium Green s functions; Gain clamping; Fysicumarkivet A:2016:Winge; kvantkaskadlaser; terahertz; infrarött; Halvledarfysik; spektroskopi; simulering;

    Sammanfattning : This thesis adresses modeling of quantum cascade lasers using non-equilibrium Green’s functions. Focus lies on the quantitative modeling of the gain when the systems are exposed to strong laser fields, as under realistic opertional conditions. LÄS MER

  4. 18. Runaway electrons and Alfvén eigenmodes in tokamaks

    Författare :Håkan Smith; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; two-way diffusion equation; compressional Alfvén eigenmode; fusion plasma physics; tokamak disruption; runaway electron; Alfvén cascade;

    Sammanfattning : Runaway electrons can be generated as a consequence of the rapid thermal quench of the plasma in a tokamak disruption. If the time scale of this cooling is short compared to the collision time in the tail of the electron velocity distribution, incomplete thermalisation of this tail leads to a burst of runaway production. LÄS MER

  5. 19. Investigating Time-Varying Processes Using Seismicity and Time-Dependent Tomography

    Författare :Alex Hobé; Ari Tryggvason; Olafur Gudmundsson; Roland Roberts; Nicholas Rawlinson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Time-Dependent Tomography; Joint Inversion; Geothermal Energy; Volcanotectonics; Seismic Unrest; Fagradalsfjall Eruption; Geofysik med inriktning mot seismologi; Geophysics with specialization in Seismology;

    Sammanfattning : Our global society is affected by, and makes use of, many time-varying processes. Processes related to geothermal energy and CO2 sequestration can help mitigate climate change and reduce the number of premature deaths (millions annually) due to air pollution from fossil fuels. LÄS MER

  7. 20. Leveraging HVPE for III-V/Si Integration and Mid-Infrared Photonic Device Fabrication

    Författare :Axel Strömberg; Yan-Ting Sun; Sebastian Lourdudoss; Mattias Hammar; Charles Cornet; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; HVPE; III-V Si; Photovoltaics; PEC; MIR; non-linear optics; QPM; QCL; Energiteknik; Energy Technology;

    Sammanfattning : This work covers the implementation of highly specialized epitaxial techniques enabled by the near-equilibrium hydride vapor-phase epitaxy growth process in III-V/Si integration for Si-based tandem solar cells and photoelectrochemical reactions, quasi phase matching GaP structures on GaAs substrates, and regrowth of InP:Fe on quantum cascade lasing structures.III-V/Si integration is an important topic in several fields of research with a significant one being solar energy harvesting. LÄS MER