Papers in this group
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Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks (STs). Using the increased heating capabilities PNBI 3.8 MW H-mode at Ip =…
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Results from START at Culham have been very impressive and have triggered the construction of several new Spherical Tokamaks (R/a51.5), including the Mega Amp Spherical Tokamak (MAST), which was given EU- RATOM approval in April 1996. MAST (R= 0.7…
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The theory of neoclassical transport in an impure toroidal plasma is extended to allow for larger pressure and temperature gradients and faster toroidal rotation than are usually considered. Under these conditions, the density of heavy impurities is…
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Transport analysis of MAST discharges indicates that ion collisional transport is an important loss mechanism in the core of a spherical tokamak. In the strongly-varying equilibrium fields of spherical tokamaks many of the assumptions of drift…
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The physical mechanism behind the bootstrap current is explained, and the consequences are discussed with the emphasis on the two main objectives of fusion plasma, confinement and MHD stability. For a tokamak reactor that is optimized for good…
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Calculations of collisional diffusivities in toroidal magnetic plasma confinement devices order the toroidal gyroradius to be small relative to the poloidal gyroradius, i.e., $\rho_{i\phi} \ll \rho_{i\theta}$, where $\rho_{i\phi} =…
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For plasma with a large number of degrees of freedom, particle simulation using high-speed computers can offer insights and information that supplement those gained by traditional experimental and theoretical approaches. The technique follows the…
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Conservation of canonical angular momentum is shown to require that all trapped particles drift towards the magnetic axis with vcelocity cEt/Bp (Et is the toroidal electric field; Bp the poloidal magnetic field). this property, plus an amplification…
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Nonlinear gyrokinetic equations play a fundamental role in our understanding of the long-time behavior of strongly magnetized plasmas. The foundations of modern nonlinear gyrokinetic theory are based on three pillars: (i) a gyrokinetic Vlasov…
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A nonlinear electrostatic gyrokinetic Vlasov equation as well as a Poisson equation have been derived in a form suitable for particle simulation studies of tokamak microturbulence and associated anomalous transport. This work differes from the…
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Wendelstein 7-AS was the first modular stellarator device to test some basic elements of stellarator optimization: a reduced Shafranov shift and improved stability properties resulted in β-values up to 3.4% (at 0.9 T). This operational limit was…
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This overview is an assessment of the gyrokinetic framework and simulations to compute turbulent transport in fusion plasmas. It covers an introduction to the gyrokinetic theory, the principal numerical techniques which are being used to solve the…
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Guiding-center theory provides the reduced dynamical equations for the motion of charged particles in slowly varying electromagnetic fields, when the fields have weak variations over a gyration radius or gyroradius in space and a gyration period or…
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Ideal magnetohydrodynamic theory and its application to magnetic fusion systems are reviewd. The review begins with a description and derivation of the model as well as a discussion of the region of validity. Next, the general properties are derived…