Coherent structures and anomalous transport in reversed field pinch plasmas
نویسندگان
چکیده
The results leading to the identification of coherent structures emerging from the background turbulence in the edge region of the reversed field pinch experiments EXTRAP-T2R and RFX are reviewed. These structures have traits of vortices in velocity field and blobs in density, and the reconstruction of their spatial structure and of their time evolution is discussed focusing on the analysis tools applied. The role of these structures in the particle anomalous transport is addressed, showing that their collisions can contribute up to 50% the total particle losses. This process is shown to be responsible for bursts in particle flux and it is found to set a characteristic collision time, which is in agreement with the statistical properties of laminar times for particle flux bursts. PACS numbers: 52.35.Ra, 52.25.Fi, 52.35.We
منابع مشابه
On the delayed gas breakdown in a ringing theta-pinch with bias magnetic field
Related Articles Resistivity in the dynamic current sheath of a field reversed configuration Phys. Plasmas 19, 032511 (2012) Plasma flow structures as analytical solution of a magneto-hydro-dynamic model with pressure Phys. Plasmas 19, 032506 (2012) Electron density and plasma dynamics of a spherical theta pinch Phys. Plasmas 19, 033505 (2012) Modeling the Parker instability in a rotating plasm...
متن کاملAnomalous impurity ion heating from Alfvénic cascade in the reversed field pinch
Anomalous ion and impurity heating in reversed field pinch plasmas is addressed. Previous work #N. Mattor et al., Comments Plasma Phys. Controlled Fusion 15, 65 !1992"$, which calculated the heating of bulk ions by gyro and Landau resonances with turbulent fluctuations cascading from unstable tearing modes, is extended to impurity species measured in Madison symmetric torus !MST". The heavier m...
متن کاملMomentum transport and flow damping in the reversed-field pinch plasma
A biased electrode is used in the Madison Symmetric Torus ~MST! reversed-field pinch @Fusion Technol. 19, 131 ~1991!# to manipulate plasma flow in order to study flow damping and momentum transport. Finite radial conductivity allows a radial current, which provides the toroidal torque that spins up the plasma. The applied torque is balanced by a viscous force that opposes toroidal flow accelera...
متن کاملTurbulent particle transport in magnetized plasmas.
Particle transport in magnetized plasmas is investigated with a fluid model of drift wave turbulence. An analytical calculation shows that magnetic field curvature and thermodiffusion drive an anomalous pinch. The curvature driven pinch velocity is consistent with the prediction of turbulence equipartition theory. The thermodiffusion flux is found to be directed inward for a small ratio of elec...
متن کاملObservation of velocity-independent electron transport in the reversed field pinch.
Confinement of runaway electrons has been observed for the first time in a reversed field pinch during improved-confinement plasmas in the Madison Symmetric Torus. Energy-resolved hard-x-ray flux measurements have been used to determine the velocity dependence of the electron diffusion coefficient, utilizing computational solutions of the Fokker-Planck transport equation. With improved-confinem...
متن کامل