Sökning: "toroidal instabilities"

Visar resultat 16 - 20 av 24 avhandlingar innehållade orden toroidal instabilities.

  1. 16. Drift and Mirror Modes in Magnetized Plasmas

    Författare :Ingmar Sandberg; Padma Shukla; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; tokamak plasma; drift waves; space plasma; mirror instability.; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space and Plasma Physics; rymd- och plasmafysik;

    Sammanfattning : Low frequency plasma instabilities driven by plasma inhomogeneity and velocity anisotropies are major candidates for the explanation of various phenomena observed in fusion and space plasmas. For low-β fusion plasma, the influence of plasma rotation and finite ion temperature on the structure and the type of toroidal drift eigenmodes in tokamaks is investigated rigorously, including the effects induced by the toroidal geometry such as the coupling mode, the radial variation of plasma rotation velocity and the magnetic shear. LÄS MER

  3. 17. Stabilisation of resistive-wall modes in fusion plasmas

    Författare :Demetrio Gregoratto; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electromagnetic feedback control; Tokamak; resistive-wall mode; reversed field pinch; MHD;

    Sammanfattning : For the success of thermonuclear fusion by magnetic confinement it is important to improve on the stability limits imposed by large-scale magnetohydrodynamics (MHD) instabilities. This thesis focuses on the stabilisation of the "resistive-wall mode" (RWM), an instability which affects high-pressure tokamaks but also Reversed Field Pinches (RFP). LÄS MER

  4. 18. Diagnosing Fuel Ions in Fusion Plasmas using Neutron Emission Spectroscopy

    Författare :Carl Hellesen; Göran Ericsson; Sean Conroy; William W Heidbrink; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; fusion; plasma diagnostics; neutron spectroscopy; NBI heating; ICRF heating; energetic ions; Fusion; Fusion; Nuclear physics; Kärnfysik; Applied Nuclear Physics; Tillämpad kärnfysik;

    Sammanfattning : Neutron emission spectra, measured with the time of flight spectrometer TOFOR, at the joint European torus (JET) are presented in this thesis. TOFOR has been in use since 2005, routinely measuring the neutron emission from JET plasmas. LÄS MER

  5. 19. Microinstabilities in Advanced Tokamak and Stellarator Geometries

    Författare :Ansar Mahmood; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tokamaks; microinstabilities; fusion plasmas; ITG; drift waves; stellarators;

    Sammanfattning : The anomalous particle and heat transport observed in magnetically confined plasmas is generally attributed to plasma turbulence driven by short-scale instabilities, called microinstabilities. Understanding the stability limits of microinstabilities and their dependency on the equilibrium configuration is of paramount importance in the effort to predict the performance of future fusion devices such as the International Thermonuclear Experimental Reactor (ITER). LÄS MER

  7. 20. Fast ions and turbulent particle transport in tokamaks

    Författare :Frida Eriksson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NBI; numerical modelling; turbulence; drift waves; bump-on-tail; density peaking; Fusion plasma physics; wave-particle interaction;

    Sammanfattning : The presence of highly energetic (fast) ions, be it fusion born alpha particles or ions accelerated by auxiliary heating schemes, can affect the heating and transport of all particles in the plasma through two main mechanisms. First, fast ions may excite fast ion driven instabilities. LÄS MER