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Ion distributions in a loss cone are measured in the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985)]. When Alfven ion cyclotron (AIC) modes are excited in the central cell, enhanced end-loss of ions is observed for a characteristic energy region which agrees well with the resonant ion cyclotron condition with the AIC wave. From measurements of pitch angle distributions of end-loss ions, it is found that the loss cone is filled for this characteristic energy region, indicating an ion diffusion in a velocity space induced by the AIC wave. Magnitude of the observed additional end-loss increases with increase in the amplitude of the AIC modes. In the present experimental parameters in GAMMA 10, the AIC wave effect on the axial ion confinement is not serious.

A gold neutral beam probe system was improved by adopting a multichannel ion detector and adding sweeping functions of beam energy, deflector voltage, and electrode voltage of the analyzer to the system to measure the fluctuations and time evolution of the two-dimensional space potentials with fast resolving time during one shot. Positions of the beam spot on the multichannel detector corresponding to the ionizing points of the beam in the plasma were simulated precisely as a function of the beam energy and the injection angle. A potential derivation formula was determined taking into consideration both the numerical and experimental results, and the reproducibility of the potential profile was checked. Two-dimensional potential profiles were measured in the optimization experiment of the microwave injection angles for formation of the plug potential.

A charge exchange neutral particle analyzer including a newly designed multichannel 63.6° cylindrical electrostatic energy analyzer was constructed. Since the energy analyzer can simultaneously adopt a small radius of cylindrical electrodes and a large width of an entrance slit, high incident current can be analyzed while the size of the analyzer remain compact. Characteristics of the analyzer were investigated using hydrogen beam with energies from about 0.5 to 5 keV. The experimental results are compared well with the numerical analysis.

A new type of compact electrostatic cylindrical energy analyzer originally providing a deflection angle of π/22 has been designed with the aim of measuring energy spectra of charge exchange neutral particles in the tandem mirror GAMMA10. The essential advantage of the use of this analyzer is that a large entrance aperture can be adopted with high energy resolution so that high incident current is analyzed, while the radius of the cylindrical electrodes remain compact. Characteristics of the analyzer are discussed using computer simulations of ion trajectories including an effect of fringing field obtained by finite-element method as well as small-angle scattering in stripping collisions of hydrogen atoms.

A thermoelectric cooling system usually consists of a thermoelectric cooler (TEC) and heat exchangers at the cold side and the hot side. Heat exchangers in TEC systems are designed to minimize their thermal resistance under restrictions such as the size of the system and heat transfer method, because as the thermal resistances of heat exchangers increase, the performance of TEC systems decreases. In the TEC system in which thermal resistance of heat exchangers is minimized, the optimum TEC is analyzed to maximize the coefficient of performance (COP) and the exergetic efficiency in absorbing a given heat load. The effects of the thermal resistance of heat exchangers on the performance of the TEC system and the design parameters of that system are also investigated. To discuss these matters, dimensionless entropy flow equations of the TEC system are introduced, and the COP and the exergetic efficiency are expressed as a function of dimensionless quantities by using these dimensionless equations.

Anisotropic thermoelectric characteristics of a sintered Bi2Te3 system have been evaluated on the basis of the orientation distribution of crystallites. Uniaxially anisotropic resistivities, Hall coefficients, and thermal conductivities of sintered Bi2Te3 were expressed by linear combinations of those of single crystal. The combination coefficients are specified by an anisotropy parameter that may be estimated by the anisotropy in the observed resistivities. Two types of x‐ray diffraction experiments were performed to confirm the validity of the estimate. The observed diffraction intensities were reasonably consistent with the orientation distribution predicted by the anisotropy parameter. Theoretical curves of resistivities, Hall coefficients, and thermal conductivities of the sintered material were calculated by using the orientation distribution which was specified by a parameter estimated by the observed resistivities. The theoretical curves were in reasonable agreement with the observed data.

The relevant results [M. Yamanashi (J. Appl. Phys. 80, 5494 (1996)] are correct because the numerical simulations were performed by using dimensionless thermoelectronic cooling (TEC) system equations. These equations can be used to optimize a TEC in a TEC system when p- and n-type thermoelements have different geometrical factors (lp/Sp≠ln/Sn). Usefulness of exergetic efficiency and the definition of the maximum dimensionless entropy flow are also explained.