Numerical and analytical interpretation of rotation and radial electric fields in collision dominated edge plasmas
Germany
Numerical and analytical interpretation of rotation and radial electric fields in collision dominated edge plasmas
The ambipolarity constraint and the parallel momentum balance equation of neoclassical theory, accounting for finite Larmor radius effects and inertia, allow to describe the radial electric field and the related spin up in collision dominated edge - plasma with steep gradients. Thus they may contribute significantly to the understanding of the L-H ...
Finite Larmor-radius theory of magnetic island evolution
United Kingdom
Finite Larmor-radius theory of magnetic island evolution
In this paper, we present the first kinetic analysis of nonlinear magnetic island evolution that includes the effect of the excitation of drift waves and extends over the complete range of frequencies comparable to the drift frequency. Our analysis brings to light three new phenomena that have important implications for our understanding of island ...
One and two dimensional studies of the collisionless large Larmor radius Z pinch
United Kingdom
One and two dimensional studies of the collisionless large Larmor radius Z pinch
This thesis reports computational and analytical studies of the collisionless large Larmor radius [LLR] Z pinch. There are two particularly important aspects of the physics studied here, namely collisionless LLR ions and sheared axial ion flow. The results fall into two main sections. These are 1D implosion simulations and studies of the non-linear...
The stability of Z-pinches with equilibrium flows
United Kingdom
The stability of Z-pinches with equilibrium flows
According to Ideal Magnetohydrodynamic (MHD) theory the Z-pinch is an inherently unstable magnetic configuration. However it is possible that there exist regimes of operation whereby the predicted instabilities may be reduced or even eliminated. We must look to effects normally ignored in the Ideal MHD model in order to predict such regimes. In thi...
Linear propagation and absorption of the fast wave near the first ion cyclotron harmonic
We investigate wave propagation and absorption in the vicinity of the first ion cyclotron harmonic resonance. Two regimes, dominated by mode conversion to Bernstein waves and by ion cyclotron damping, respectively, are identified, depending on the value of k _p_a_r_a_l_l_e_l and the density and temperature of resonant ions. With the help of analyti...
Linear propagation and absorption of the fast wave near the first ion cyclotron harmonic
Germany
