Sökning: "magnetic viscosity"

Visar resultat 1 - 5 av 26 avhandlingar innehållade orden magnetic viscosity.

  1. 1. Resonant magnetic perturbation effect on the tearing mode dynamics : Novel measurements and modeling of magnetic fluctuation induced momentum transport in the reversed-field pinch

    Författare :Richard Fridström; Per Brunsell; Lorenzo Frassinetti; Tommaso Bolzonella; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; RFP; reversed-field pinch; tokamak; tearing mode; RMP; fusion; plasma; resonant magnetic perturbation; stochastic; magnetic; field; viscosity; mode; locking; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : The tearing mode (TM) is a resistive instability that can arise in magnetically confined plasmas. The TM can be driven unstable by the gradient of the plasma current. When the mode grows it destroys the magnetic field symmetry and reconnects the magnetic field in the form of a so-called magnetic island. LÄS MER

  3. 2. Magnetic deflagration and detonation in crystals of nanomagnets

    Författare :Oleksii Iukhymenko; Claude Dion; Javier Tejada; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nanomagnets; magnetic deflagration; front instability; Zeeman energy; magnetic instability; magnetic detonation; weak detonation; Physics Of Matter; materiefysik;

    Sammanfattning : In this thesis we cover the dynamics of the macro magnetic transformations (spin avalanches) in crystals of molecular nanomagnets, also known as magnetic deflagration and detonation.Taking a single-molecule Hamiltonian, we calculate the dependence of Zeeman energy and the activation energy as a function of an external magnetic field at different angles relative to the easy axis of the crystal. 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. Local structure and composition : in additively manufactured bulk metallic glasses and composites

    Författare :Inga Katharina Goetz; Jochen M. Schneider; Björgvin Hjörvarsson; Ulf Jansson; Maria Teresa Pérez Prado; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; additive manufacturing; bulk metallic glasses; nanoscale clustering; convective flow; laser nitriding; laser powder bed fusion; metallic glass - ceramic composites; oxygen impurities; mechanical properties; magnetic properties; viscosity; Fysik; Physics;

    Sammanfattning : Additive manufacturing enables the production of complex multi-material geometries and bulk metallic glass parts beyond their critical casting thickness. The local modification of structure, composition, and properties is explored in this thesis with the aim to design novel composite materials and functional gradients. LÄS MER

  7. 5. SmCo for polymer bonded magnets : Corrosion, silanization, rheological, mechanical and magnetic properties

    Författare :Muhammad Irfan Qadeer; Steven Savage; Mikael Hedenqvist; Uta Klement; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Organofunctional alkoxysilanes; High temperature oxidation; Rare-earth magnetic alloys; SmCo; Isothermal; Non-isothermal; Microstructure; Magnetic properties;

    Sammanfattning : This thesis presents the study of organofunctional alkoxysilane coatings to prevent high temperature oxidation of Sm-Co powders. Sm-Co are important permanent magnetic alloys, owing to their high Curie temperature and large values of magnetocrystalline anisotropy. LÄS MER