[en] Some of the constraints are examined on fusion reactions, plasma confinement systems, and fusion reactors that are intended for such space related missions as manned or unmanned operations in near earth orbit, interplanetary missions, or requirements of the SDI program. Of the many constraints on space power and propulsion systems, those arising from safety and environmental considerations are emphasized since these considerations place severe constraints on some fusion systems and have not been adequately treated in previous studies

[en] A preliminary report on the identification and optimization of independent variables which affect the ion density and confinement time in a bumpy torus plasma is presented. The independent variables include the polarity, position, and number of the midplane electrode rings, the method of gas injection, and the polarity and strength of a weak vertical magnetic field. Some characteristic data taken under condition when most of the independent variables were optimized are presented. The highest value of the electron number density on the plasma axis is 3.2 x 10 to the 12th power/cc, the highest ion heating efficiency is 47 percent, and the longest particle containment time is 2.0 milliseconds

[en] The degree of toroidal symmetry of the plasma, the number of midplane electrode rings, the configuration of electrode rings, and the location of the diagnostic instruments with respect to the electrode rings used to generate the plasma are discussed. Impurities were deliberately introduced into the plasma, and the effects of the impurity fraction on ion kinetic temperature and electron number density were observed. It is concluded that, if necessary precautions are taken, the plasma communicates extremely well along the magnetic field lines and displays a high degree of symmetry from sector to sector for a wide range of electrode ring configurations and operating conditions. Finally, some characteristic data taken under nonoptimized conditions are presented, which include the highest electron number density and the longest particle containment time (1.9 msec) observed. Also, evidence from a paired comparison test is presented which shows that the electric field acting along the minor radius of the toroidal plasma improves the plasma density and the calculated containment time more than an order of magnitude if the electric field points inward, relative to the values observed when it points (and pushes ions) radially outward

[en] The potential applications of fusion reactors, the desirable properties of reactors intended for various applications, and the limitations of the Tokamak concept are discussed. The principles and characteristics of 20 distinct alternative confinement concepts are described, each of which may be an alternative to the Tokamak. The devices are classed as Tokamak-like, stellarator-like, mirror machines, bumpy tori, electrostatically assisted, migma concept, and wall-confined plasma

[en] Experimental observations were made during steady state operation of a torus experiment at input powers up to 150 kilowatts in deuterium and helium gas. The steady state ion heating method utilizes a modified Penning discharge operated in a bumpy torus confinement geometry. The bumpy torus plasma is acted upon by a combination of strong electric and magnetic fields. In a deuterium plasma, electron temperatures from 14 to 140 electron volts and ion kinetic temperatures from 160 to 1785 electron volts were observed. At least two distinct operating regimes exist, each of which is associated with a characteristic range of background gas pressure and electron temperature. Experimental data show that the average ion residence time in the plasma is virtually independent of magnetic field strength. (auth)

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No abstract available

[en] The toroidal ring of plasma contained in the NASA Lewis bumpy-torus superconducting magnet facility may be biased to positive or negative potentials approaching 50 kilovolts by applying direct-current voltages of the respective polarity to 12 or fewer of the midplane electrode rings. The electric fields which are responsible for heating the ions by E/B drift then point radially outward or inward. The low-frequency fluctuations below the ion cyclotron frequency appeared to be dominated by rotating spokes. (Author)

[en] Radio frequency emission has been detected near the power hybrid frequency of a bumpy torus plasma by using a responsive detection system that consists of a spectrum analyzer and a 50 ohm miniature coaxial antenna concentrically located in a re-entrant quartz tube. The frequency shift of a broad emission peak was monitored as a function of background pressure, electrode voltage, and the strength of the dc magnetic field. Simultaneous measurements of the average plasma density were made with a polarization diplexing microwave interferometer. The information derived from the experiment is discussed with particular reference to the following: (1) whether the emissions are dominated by atomic or molecular species of deuterium; (2) the strength of the dc magnetic field in the emitting region; (3) the geometric location of the emitting region of the plasma; (4) comparison of the lower hybrid plasma density with the average plasma density; and (5) relation of ion spoke geometry to lower hybrid emission

[en] The Electric Field Bumpy Torus (EFBT) plasma is capable of producing steady-state fluxes of Maxwellianized ions with kinetic temperatures on the order of a keV, and can do so at an ion heating cost of 10 cents per watt. These ions can be supplied at fluxes which equal or exceed those characteristic of space-charge limited ion sources. The deuterium ion fluxes measured at the surface of the EFBT plasma have been as high as 5 x 10¹⁹ ions/M²-sec (8.0 amps/M²) in the steady-state, and on the order of 2 x 10²² ions/10²² M²-sec (3200 amps/M²) on the electrode surfaces. This plasma has achieved average number densities up to 3 x 10¹² ions per cubic centimeter, and ion kinetic temperatures up to 500 eV for the above fluxes. The EFBT plasma is therefore an attractive candidate to supply large fluxes and fluences of ions for studies related to divertors, limiters, and first wall bombardment