Toroidal confinement

There are three different toroidal confinement configurations, each of them being a potential route to a possible fusion power plant ... 

The third class of toroidal confinement devices is the stellarator which differs in an essential way from tokamaks and RFPs in that the helical fields are created entirely by coils external to the plasma, with no net toroidal current following within the plasma. 

Interest in the compact torus (CT) for fusion rests on forming an axisymmetric, closed, toroidal-confinement-region for plasma within a nearly uniform external field as shown in Fig. 1. The advantages of toroidal confinement are thereby obtained while retaining reactor-related simplifications in blanket and coil design and natural plasma diversion because of the open-ended external field. To achieve these dual advantages, the toroidal confinement fields must be formed by plasma currents, rather than... 

There has been a recent increase in interest in the CT in the United States. This interest stems from the successful demonstration of toroidal confinement in Tokamaks and FRC s formed with theta-pinches, and from a renewed desire to investigate confinement configurations with simplified reactor consequences. In this section I will summarize experimental studies in the United States under the broad categories, CT s... 

Also in 1950 Sakliarov and Tamm proposed an idea for a controlled thermonuclear fusion reactor, the TOKAMAK (acronym for the Russian phrase for toroidal chamber with magnetic coiF ), which achieved the highest ratio of output power to input power of any fusion device of the twentieth centuiy. This reactor grew out of interest in a controlled nuclear fusion reaction, since 1950. Sakharov first considered electrostatic confinement, but soon came to the idea of magnetic confinement. Tamm joined the effort with his work on particle motion in a magnetic field, including cyclotron motion, drifts, and magnetic surfaces. Sakharov and Tamm realized that... 

Axons of male-specific antennal ORCs specialized to detect components of the sex pheromone project exclusively to the MGC (64, 89), and all AL neurons that respond to antennal stimulation with sex pheromone components have arborizations in the MGC (65, 72, 73). The MGC in M. sexta has two major, easily distinguishable divisions a donut-shaped neuropil structure (the "toroid") and a globular structure (the "cumulus") adjacent to the toroid and closer to the entrance of the antennal nerve into the AL (74). AL PNs that respond to antennal stimulation with sex pheromone component A have arborizations in the toroid and PNs responsive to component B, in the cumulus (74). Thus first-order synaptic processing of sensory information about these key components of the sex pheromone apparently is confined to different, distinctive neuropil regions of the MGC. 

Choi MC et al (2004) Ordered patterns of liquid crystal toroidal defects by microchannel confinement. Proc Natl Acad Sci USA 101(50) 17340-17344... 

The stellarators are similar to Tokamaks, both employing a closed toroidal magnetic field for basic plasma confinement. The stabilization in stellarators is, however, provided by special helical windings16. They possess some potential advantages as compared to the Tokamaks with respect to confinement properties and the possibility of steady state operation. Technical and technological limitations such as the small size of the presently available stellarators and the lack of appropriate, sufficiently intense heating systems have inhibited progress comparable to that which Tokamaks have so far achieved. 

Fig. 2.6. Top section of computational domain for TEXTOR model, showing also the cross-section of the toroidal ALT-II limiter 45 degrees underneath the outer mid-plane. Bottom computed Balmer-alpha emission profile (photons/s/cm3, logarithmic colour scale) in the TEXTOR edge plasma, as used for interpretation of visible spectroscopy [26] and determination of plasma particle confinement...

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