General Physics Seminar 28 October 2004


Fast magnetic reconnection in hot plasmas

Hugo de Blank
FOM-Institute for Plasma Physics Rijnhuizen


Magnetic confinement of hot plasma is the basis of the most successful controlled fusion experiments. Plasma instabilities can spontaneously perturb the magnetic field and as it turns out, perturbed fields continue to confine the plasma only thanks to the high electric conductivity at high plasma temperatures. Break-up and reconnection of magnetic field lines is the exception rather than the rule, but reconnection in thin layers in fusion plasmas is nevertheless a key mechanism for the observed high energy losses. Magnetic reconnection is also the mechanism that releases thermal and magnetic energy from the solar corona and the Earth's magnetosphere. The seminar will briefly sketch how observed magnetic reconnection rates can be much higher than was previously predicted theoretically. Then, it will be shown how temperature gradients affect magnetic reconnection and the release of thermal energy. This novel mechanism may enable the temperature distribution and magnetic field to self-organize and help explain the complex behaviour seen in fusion experiments.