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The principle of Project MACETIE and the preliminary experiment are described. The basis of our plan is the thought that the goal of controlled thermonuclear fusion may be accessible by the multistage alternating processes of adiabatic compression and irreversible expansion of plasma. In the latter process, the plasma compressed by a strong magnetic field is expanded into a region of weaker magnetic field. A static consideration of this expansion suggests that plasma temperature will not change appreciably in this process, and a second adiabatic compression of plasma in the weak field may further increase its temperature. Preliminary experiments are being carried out to examine the foregoing principle of irreversible expansion.

Spase and time resolved Mach-Zebnder interferometer is applied to study a slow theta pinch plasma. Methods of timing operations and experimental arrangements are described. The plasma is pinched in the third half cycle of discharge period. The interferogram shows that the peak electron density varies from about 1 x 1016 to 1 x 1017 cm-3 as the filling gas pressure is varied from 25 to 400 mtorr. The radial distribution of shell structure is observed when a small reverse bias field is added. The relaxation time of this field is longer at the lower gas pressure. In the pressure range of higher than 40 mtorr, a flute-type instability appears. But no drift motions are observed. Interferograms show various modes of instabilities. The loss rate of the total number of electrons is estimated and the result is in good agreement with a theoretical model of steady magnetohydrodynamic fluid.

For the measurement of a profile of spectral line, a high dispersive monochrometer with an Echelle-grating and 12 channels of photoelectric devices using thin glass sheets, to separate the line profile are constructed. The measured resolving power is about 2×105 and the linear dispersion at the image plane is 1.2 mm/A. This instrument is applied to measure the ion temperature of MACETIE device by using the line of He II 4686 A.

Turbulent spectrum of ion waves excited by an electron current is investigated experimentally, where electron drift velocity is measured directly by the rotatable Langmuir probe.

The effective scattering of an ion beam by the ion wave turbulence is investigated experimentally. The results are compared with the values predicted theoretically.

For the measurement of the profile of a spectral line, a high dispersive monochromator with an Echelle grating and 12 channels of photoelectric devices using thin glass sheets to separate the line profile was constructed. The measured resolving power is about 2×105 and the linear dispersion at the image plane is 1.2 mm/Å at 5000Å. This instrument was used to measure the ion temperature of a BSG device by employing the 4686Å line of He II.

Electron temperatures as well as plasma densities of a transient plasma can be visualized directly on the pattern of a cathode-ray tube. The principle is based on Langmuir's single probe method. Electron temperature is obtained by differentiating a logarithm of the probe current with respect to the probe potential. Then, if the probe potential is changed linearly with time, electron temperature is given by the ratio of probe current to its time derivative. (L.T.W.)

N-type indium antimonide shows the photoconductive effect not only in the far infrared, but also in the millimeter-wave region. Millimeter-wave photoconductivity was observed in the 2 mm-wave region to clarify the origin of the effect. It is concluded that, in elements with low carrier concentration, the impurity transition between shallow donor levels is the main process for the photoconductivity, while the hot electron photoconductive effect is small as compared with the impurity photoconductivity. Performances as a millimeter-wave detector are also studied. Signal-to-noise ratio of InSb detector is superior to that of conventional silicon point contact diode. Rise and decay times of the detector without magnetic field are about 0.4 µs and 0.7 µs respectively. This detector is useful even for measurements of incoherent radiation.