Sökning: "MHD modes"

Visar resultat 1 - 5 av 17 avhandlingar innehållade orden MHD modes.

  1. 1. 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

  3. 2. Resistive Wall Mode Stability and Control in the Reversed Field Pinch

    Författare :Dmitriy Yadikin; Per Brunsell; Mikhail Gryaznevich; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Resistive wall modes; RWM; active control; feedback; MHD modes; Reversed-Field pinch; RFP; intelligent shell; mode control; Electrophysics; Elektrofysik;

    Sammanfattning : Control of MHD instabilities using a conducting wall together with external magnetic fields is an important route to improved performance and reliability in fusion devices. Active control of MHD modes is of interest for both the Advanced Tokamak and the Reversed Field Pinch (RFP) configurations. LÄS MER

  4. 3. Tearing mode dynamics in the presence of resonant magnetic perturbations

    Författare :Richard Fridström; Per Brunsell; Marco Cecconello; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tearing mode; plasma; fusion; reversed-field pinch; RFP; magnetic; confinement; resonant; perturbation; magnetohydrodynamics; MHD; EXTRAP T2R; Madison Symmetic Torus; Fysik; Physics;

    Sammanfattning : Magnetically confined fusion (MCF) plasmas are typically subject to several unstable modes. The growth of one mode can limit the plasma energy confinement and might cause a termination of the plasma. Externally applied resonant magnetic perturbations (RMPs) are used to control and to mitigate some of the unstable modes. LÄS MER

  5. 4. Non-linear dynamics of Alfvén eigenmodes excited by fast ions in tokamaks

    Författare :Tommy Bergkvist; Torbjörn Hellsten; Fulvio Zonca; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fusion plasma; tokamak; MHD; toroidal Alfvén eigenmodes; thermonuclear alpha particles; ion cyclotron resonance heating; Electrophysics; Elektrofysik;

    Sammanfattning : The tokamak is so far the most promising magnetic configuration for achieving a net production of fusion energy. The D-T fusion reactions result in 3.5 MeV alpha-particles, which may destabilize Alfvén eigenmodes through wave-particle interaction. LÄS MER

  7. 5. Pressure driven instabilities in the reversed-field pinch : numerical and theoretical studies

    Författare :Ahmed Akram Mirza; Jan Scheffel; Roberto Paccagnella; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fusion plasma; thermonuclear; Reversed-field pinch; resistive MHD; resistive g modes; thermal conduction; the boundary value theory;

    Sammanfattning : According to classical linearized resistive magnetohydrodynamics theory, pressuredriven modes are unstable in the reversed-field pinch (RFP) due to unfavorable magnetic field line curvature. The result is based on the assumption of an adiabatic energy equation where anisotropic thermal conduction effects are ignored as compared to convection and compression. LÄS MER