[en] The present paper reviews recent laboratory experiments on magnetic reconnection. Examples will be drawn from electron current sheet experiments, merging spheromaks, and from high temperature tokamak plasmas with the Lundquist numbers exceeding 10⁷. These recent laboratory experiments create an environment which satisfies the criteria for MHD plasma and in which the global boundary conditions can be controlled externally. Experiments with fully three dimensional reconnection are now possible. In the most recent TFTR tokamak discharges, Motional Stark effect (MSE) data have verified the existence of a partial reconnection. In the experiment of spheromak merging, a new plasma acceleration parallel to the neutral line has been indicated. Together with the relationship of these observations to the analysis of magnetic reconnection in space and in solar flares, important physics issues such as global boundary conditions, local plasma parameters, merging angle of the field lines, and the 3-D aspects of the reconnection are discussed

[en] The S-1 device inductively generates spheromak plasmas with major radii of 40 to 65 cm and toroidal plasma currents up to 500 kA. The major objective is the investigation of MHD stability and transport characteristics of spheromaks that are stabilized in externally applied magnetic fields by loose-fitting conductors and coils

[en] The QED-1 device at PPL has provided gettering efficiency data for neutralized hydrogen plasma on titanium. The hollow-anode arcjet produces a plasma column 1 cm in diameter with 10¹² < n/sub e/ < 10¹⁵ cm^-3 and T/sub i/ approx.< T/sub e/ = 3-10 eV, confined by an axial magnetic field of 1-6 kG. The gettering measurements are based on monitoring neutral gas density with respect to time in the divertor simulation chamber of QED-1. The present results indicate that the plasma particles lose their charge and most of their energy when they strike the neutralizer plate

[en] The evolution and effects of current-driven instabilities in isothermal, inhomogeneous plasmas are investigated in both theory and experiment. Successive destabilizations of four different instabilities, low-frequency drift wave, ion-cyclotron drift wave, high-frequency (continuous-spectrum ion-cyclotron) drift wave, and high-frequency electron wave, are observed in Q-device plasmas with increased current, and explained by a theory based on fluid and kinetic equations. Anomalous effects resulting from wave-particle interactions, i.e., enhanced resistivity, ion heating and electron viscosity, are compared with predictions based on quasi-linear calculations. Analogous to ion sound causing important anomalies in the transport coefficients for plasmas with T/sub e//T/sub i/ much greater than 1, high-frequency, continuous-spectrum drift waves determine anomalous plasma behavior in inhomogeneous plasmas with T/sub e//T/sub i/ approximately equal to 1

No abstract available

[en] Preliminary design studies are carried out for a spheromak fusion reactor. Simplified circuit theory is applied to obtain characteristic relations among various parameters of the spheromak configuration for an aspect ratio A greater than or equal to 1.6. These relations are used to calculate the parameters for the conceptual designs of three types of fusion reactor: (1) DT two-component, (2) DT ignited, and, (3) catalyzed DD ignited reactors. With a total wall loading of approx. 4 MWm^-2, it is found that edge magnetic fields of only approx. 4T (DT) and approx. 9T (cat. DD) are required for ignited reactors of one-meter plasma (minor) radius with output powers in the gigawatt range. Assessment of various methods of generating reactor-grade spheromak plasmas is discussed briefly

[en] A suprathermal electron beam is injected parallel to vector B in a low-β plasma. The sharp space-potential drop across the surface of the beam generates a strong cross-field current which in turn drives a modified two-stream instability at the lower hybrid frequency. Intense stochastic ion heating is observed with the onset of the instability, and the heating rate is found to be proportional to the wave energy

[en] A lower-hybrid instability with ion cyclotron harmonics is observed to be driven by an ion beam injected obliquely to the magnetic field confining the isothermal plasma of the Q-1 double plasma device. The instability occurs with the injection of a low density, low velocity beam and propagates normal to the field with phase velocity ω/k/sub perpendicular/ approximately equal to u/sub b//sub perpendicular/, the perpendicular velocity component of the spiraling ions. The frequency spectrum, propagation, and growth rate are all in good agreement with a numerical calculation based on linear kinetic theory. Pulsed beams are used to follow the instability from the linearly growing stage to nonlinear saturation. The anomalous perpendicular momentum loss of the beam is examined by both direct energy analysis and by measurements of the resultant beam orbit modifications. By varying the beam parameters, a transition of the nonlinear saturation mechanism from the quasilinear to the trapping regime is demonstrated

[en] The anomalous slowing of an ion beam injected perpendicularly to the confining magnetic field of a low β plasma is experimentally verified in the nonlinear stages of the excited lower-hybrid instability. Furthermore, a transition of the main nonlinear mechanism from the quasilinear to the particle trapping regime is demonstrated by varying beam parameters

[en] A permanent magnet, which comprises a composition containing a Sm-Co compound and consisting essentially of 23 to 30 wt.% of Sm, 0.2 to 1.5 wt.% Ti, 9 to 13 wt., Cu, 3 to 12 wt.% Fe and the balance Co, said magnet having a residual flux density (Br) of about 10 (kG), a coercive force (IC) of about 8 (KOe) and a maximum energy product (BH max) of about 25 (MGOe), having the aforesaid magnetic properties without the necessity of an ageing treatment