[en] An assessment is given of the present state of stellarator research in the world. Stellarators have recently been shown to be extremely effective toroidal magnetic confinement systems with high energy confinement times, flat density and temperature profiles and qs at the limiter that can be of the order of 0.5. In addition, currentless operation is effective and permits the establishment of the confining fields before plasma is introduced. No disruptive instabilities have ever been reported by present day ohmically-heated stellarators when the helical rotational transform is large enough to outweigh the current rotational transform. (U.K.)

No abstract available

[en] The behavior of stellarator/torsatron configurations in the collisionless regime is important to their viability as a fusion reactor. A summary of various predictions of the behavior of the diffusion coefficient in this regime is given together with a comparison to expected results

[en] The theory of microwave heating of a plasma in a dc magnetic field is developed as an inverse emission process. The computation of heating rates based on this theory show close agreement with those based on particle motion or conductivity. Since emission theories are well-known, the agreement provides a basis for accurately determining heating rates. In particular, measurement of peaks of emission from a plasma may be used to determine frequencies for efficient heating, provided self-absorption is considered. 9 refs

No abstract available

No abstract available

[en] The present state of stellarator research in the world is assessed. Stellarators have recently been shown to be extremely effective toroidal magnetic confinement systems with high energy confinement times, flat density and temperature profiles and qs at the limiter that can be of the order of 0.5. In addition, currentless operation is effective and permits the establishment of the confining fields before plasma is introduced. No disruptive instabilities have ever been reported by present day ohmically-heated stellarators when the helical rotational transform is large enough to outweigh the current rotational transform. (U.K.)

[en] This paper is divided into four sections, IMS results, including magnetic surface measurements, ECH breakdown characteristics, and divertor action, Proto-Cleo results, including measurements of the Pfirsch-Schlueter current and bootstrap currents, theory, including anisotropic pressure stability results, and bounce-averaged Monte-Carlo transport code development. Finally, the Proto-Cleo torsatron has been used to measure equipotential contours and possible modifications to the configuration to improve its topology

[en] Low frequency, f < 500 kHz, turbulent density fluctuations have been observed in the ohmically heated plasma of the Proto-Cleo torsatron. The power density spectrum indicates a spectral decay of the form f^-25 with no coherent modes present in the observed band. Phase spectral characteristics indicate wave number estimates which vary in magnitude and direction consistent with drift wave phenomena. Parallel wave numbers are coupled proportionally to the shear

[en] Current density profile measurements were obtained in the Proto-Cleo Torsatron (R = 40 cm, a = 5 cm, l = 3, B/sub T/ = 3 kG, anti n approx. 10¹¹ cm^-3, T/sub e/ approx. 20 eV) by using a small, back-to-back flat double probe. Three different operating circuits used with this probe are presented, along with experimental results, all showing good agreement. Current is seen to flow only within the separatrix, in channels which follow the magnetic surfaces as they move radially inward with time due to changing vertical magnetic flux