Sökning: "trapped modes"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden trapped modes.

1. 1. Acoustical Measurements of Material Nonlinearity and Nonequilibrium Recovery

   Författare :Kristian Haller; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; nonequilibrium recovery; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate; constant strain sweep;

   Sammanfattning : A damaged material or a material with non perfect atomic geometry, dislocations or cracks, exhibits two types of characteristic responses to acoustic excitations. First is the fast nonlinear dynamics response that is present as long as the material is excited. As soon as the excitation stops the response disappear. LÄS MER

3. 2. Nonlinear Acoustics Applied to NonDestructive Testing

   Författare :Kristian Haller; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear acoustics; nondestructive testing; activation density; slow dynamics; resonance frequency; nonlinear wave modulation spectroscopy; harmonic generation; trapped modes; open resonator; sweep rate;

   Sammanfattning : Sensitive nonlinear acoustic methods are suitable for material characterization. This thesis describes three nonlinear acoustic methods that are proven useful for detection of defects like cracks and delaminations in solids. LÄS MER

4. 3. Theoretical Investigation on Propagation and Coupling of Nonreciprocal Electromagnetic Surface Waves

   Författare :Kexin Liu; Sailing He; Martin Norgren; Manfred Eich; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wave propagation; coupling; magneto-optical; gyromagnetic; photonic crystal; nonreciprocity; one-way; trapped rainbow; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis aims at revealing the fundamental guiding and coupling properties of nonreciprocal electromagnetic surface waves on magneto-optical or gyromagnetic media and designing novel applications based on the properties.We introduce the background in the first chapter. LÄS MER

5. 4. Nonlinear dynamics of frequency sweeping energetic particle modes in tokamaks

   Författare :Frida Eriksson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; wave-particle interaction; Fusion plasma physics; bump-on-tail; toroidal Alfvén eigenmode; holes and clumps;

   Sammanfattning : In a burning plasma, such as the next generation tokamak experiment ITER, significant numbers of highly energetic particles will be produced via nuclear reactions. The presence of energetic particles, be it fusion born alpha particles or ions accelerated by auxiliary heating schemes, may excite kinetic instabilities and thereby affect the heating and transport of all particles in the plasma. LÄS MER

7. 5. Turbulent impurity transport in tokamak fusion plasmas

   Författare :Andreas Skyman; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; tokamaks; fluid theory; ion temperature gradient mode; impurity transport; trapped electron mode; fusion plasma physics; turbulence; e-science; Joint European Torus; gyrokinetic theory;

   Sammanfattning : With the enormous growth of high performance computing (HPC) over the last few decades, plasma physicists have gained access to a valuable instrument for investigating turbulent plasma behaviour. In this thesis, these tools are utilised for the study of particle transport in fusion devices of the tokamak variety, focusing in particular on the transport of impurities. LÄS MER