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2010
The effects of poloidal and toroidal flows on tokamak plasma equilibria are examined in the magnetohydrodynamic limit. “Transonic” poloidal flows of the order of the sound speed multiplied by the ratio of poloidal magnetic field to total field can cause the normally elliptic Grad– Shafranov GS equation to become hyperbolic in part of the solu…
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2010
In this work, the radial transport of tracers in an H-mode run in the CUTIE code [A. Thyagaraja et al. , Phys. Plasmas 12 , 090907 (2005)] is analyzed globally. Several techniques are applied to the study of the trajectories performed by the tracers, measuring the degree of self-similarity in the motion and searching for long range spatial and temp…
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2010
It is shown that the transition from L-mode to H-mode regimes in tokamaks can be reproduced using a two-fluid, fully electromagnetic, plasma model when a suitable particle sink is added at the edge. Such a model is implemented in the CUTIE code [A. Thyagaraja et al. , Eur. J. Mech. B/Fluids 23 , 475 (2004)] and is illustrated on plasma parameters t…
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2010
Inviscid, incompressible hydrodynamics and incompressible ideal magnetohydrodynamics MHD share many properties such as time-reversal invariance of equations, conservation laws, and certain topological features. In three dimensions, these systems may lead to singular solutions involving vortex and current sheets. While dissipative viscoresistive eff…
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2009
Impurity ions with sufficiently high mass in toroidally-rotating tokamak plasmas are deeply trapped by a centrifugal potential well in the outer plasma midplane, with a bounce period that is shorter than both the bounce period of magnetically-trapped ions and the collision time. As a result trace impurity ions can undergo collisional transport at a…
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2009
Equations describing the nonrelativistic motion of a charged particle in an arbitrary noninertial reference frame are derived from the relativistically invariant form of the particle action. It is shown that the equations of motion can be written in the same form in inertial and noninertial frames, with the effective electric and magnetic fields in…
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2009
It has been suggested that radial transport in turbulent plasmas may be nonlocal and non-Markovian. In this paper the transport of test particles in the global, electromagnetic, three-dimensional code CUTIE [A. Thyagaraja and et al. , Phys. Plasmas 12 , 090907 (2005)] is characterized. This code includes a nonlinear feedback mechanism between the m…
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2009
The possibility that electrons could be accelerated by inertial Alfvén waves to hard X-ray-emitting energies in the low solar corona during flares is investigated theoretically. This investigation is prompted in part by recent microwave observations indicating that the coronal magnetic field is strong enough that the Alfvén velocity c A above act…
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2008
A full orbit test-particle approach is used to study the collisional transport of impurity (carbon) ions in spherical tokamak (ST) plasmas with transonic and subsonic toroidal flows. The efficacy of this approach is demonstrated by reproducing the results of classical transport theory in the large aspect ratio limit. The equilibrium parameters used…
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2008
Showing 71 - 80 of 111 UKAEA Paper Results