Plasma Confinement Systems Research Articles

Stability of plasma confinement systems with an energetic particle component (Report on the Cornell Workshop, Ithaca, New York, 1982)

At a certain stage of maturity in the development of different fusion concepts, a unity is perceived which is lacking in the earlier, more primitive stages. Such a realization seems to have occurred to theorists investigating the stability of field-reversed particle rings, compact tori, EBT and tandem mirrors. The unifying feature in these systems is the presence of a very energetic particle component in the plasma. In the case of EBT, it is the 0.5–1.0 MeV electrons forming the stabilizing ring, for tandem mirrors it is the hot electrons in the thermal barriers, for electron rings it is the ∼ MeV electrons that provide the ring current, and for the proposed compact-torus hybrids it is the energetic large-gyroradius ions.

Conformal mapping methods in two-dimensional magnetohydrodynamics

It is demonstrated that numerically constructed conformal mappings of arbitrary simply-connected regions to a circular disk and of arbitrary doubly-connected regions onto an annulus greatly facilitate the solution of equilibrium and stability problems of axisymmetric toroidal plasma confinement systems, both for skin-current and diffuse current distributions.

Plasma confinement in stellarator systems

The stellarator is a plasma confinement system in which the magnetic field configuration is produced by currents in conductors outside the plasma. Plasma current is not necessarily required for confinement or for heating the plasma. Results from the CLEO and W VIIA experiments are presented to illustrate the progress in the understanding of containment and heating in the stellarator configuration.

Meeting of IAEA Experts on the Technology of Inertial Plasma Confinement Systems

Meeting of IAEA Experts on the Technology of Inertial Plasma Confinement Systems

The Culham superconducting levitron

A high energy plasma confinement system which uses a superconducting levitated ring to trap the plasma is described. This device, built at Culham laboratories, UK, has been operating successfully since early 1973.

New approach to magnetohydrodynamic stability: I. A practical stability concept

An equilibrium is called σ stable if growth faster than exp (σt) does not occur. On the basis of this definition a modified energy principle is obtained by means of which the stability of plasma confinement systems can be tested for times of thermonuclear interest, instead of the infinitely long times which are pertinent to the usual stability analysis. The theory is applied to the diffuse linear pinch, a theorem for σ stability is derived, and the connection with the normal-mode analysis is shown to be given with the Sturmian property, which holds for the unstable side of the spectrum, whereas the stable side consists of Sturmian and anti-Sturmian point spectra separated by continuous spectra. Growth rates and eigen-functions of Suydam modes are numerically calculated, and it is shown that violation of Suydam's criterion in the high and intermediate shear case leads to nonlocalized rapidly growing m = 1 modes. Consequently, this criterion obtains new relevance in the σ-stability analysis for this regime.

On the stability of a system in which one parameter oscillates sinusoidally with small amplitude

The study of the dynamic stabilization of certain plasma confinement and fluid systems leads to equations of the form $$(X + 2A\cos (\omega t - \phi ))y(t) + \int_0^t {R(t - t')\dot y(t')dt' = 0} $$ , whereX andA are constants, ϕ an arbitrary phase andR(t) a singular response function. This equation is solved for all values ofA and the general stability properties of the system are discussed. General formulae are given which relate the perturbed spectrum of the system to the unperturbed system. For the case where the static system has well separated eigenfrequencies, a perturbation expansion is derived.

Dynamic methods of confinement and stabilization of hot plasma

A review is given of the current state of studies of the confinement and stabilization of hot plasma using high-frequency magnetic fields in the megahertz region. The principles upon which such studies are based are summarized. A theoretical analysis is reported of a plasma confinement system using traveling-wave high-frequency fields and of the results of experiments performed with systems of this kind. Another section is devoted to dynamic plasma stabilization systems, the fundamentals of the theory of the dynamic stabilization of the Z pinch, and the results of experiments performed in this field. Experimental data are compared with the basic assumptions of the theory and certain general conclusions are reported with regard to further developments and possibilities in this subject.

Plasma Confinement Systems

Present plasma confinement systems are reviewed in order to provide an understanding of the developments necessary for demonstrating the scientific feasibility of controlled thermonuclear fusion. Significantly, these systems have several common features which appear certain to be used in more advanced experiments. These features include high field superconducting magnets, neutral beam injection, and vacuum techniques. Beyond the suppressing of plasma instabilities, improvements in these technologies will be required to achieve controlled fusion.

Dependence of Fluctuation Level on the Magnetic Field Configuration in the Spherator

The fluctuation level and the plasma confinement time were investigated by changing the shear length and average magnetic well in the spherator, a toroidal plasma confinement system. The experimental results show that the plasma is unstable when the mirror-trapped particles are located in the bad curvature section, even if the average curvature is favorable.

Toroidal Stabilized Pinch Formed with Relativistic Electrons

A plasma heating and confinement system is described which is based on a toroidal stabilized pinch formed with relativistic electrons. The pinch is formed by inducing current in a hot electron plasma confined in toroidally shaped minimum-$B$ mirror fields. For parameters achieved with a mirror-confined hot electron plasma, current in the range ${10}^{6}$ to ${10}^{7}$ A carried by 10- to 100-MeV electrons is estimated to be attainable along with heating of a dense plasma background to a multi-keV temperature.

Plasma confinement in the toroidal multipole

PLASMA CONFINEMENT SYSTEMS of various kinds have been studied in many countries for more than 15 years, with the attainment of controlled thermonuclear fusion as the aim. Most of the effort, particularly recently, has been devoted to stellarators; the largest machines are the C Stellarator at the plasma physics laboratory of Princeton University and the Tokomak at the Kurchatov Institute in Moscow. More recently experiments with toroidal multipole devices have shown that the containment time may be at least ten times that for stellarators, by reducing the loss of plasma density through “pumpout” or Bohm diffusion, a turbulence effect that had been the limiting factor of earlier machines.