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Molecular beam observations have been made of the radiofrequency spectra corresponding to reorientations of the deuteron, proton, and rotational magnetic moments in the HD molecule. For HD in the zeroth vibrational and first rotational state, these observations were made in magnetic fields of approximately 1700, 3400, and 4800 gauss. The results are found to be consistent with the theory of heteronuclear diatomic molecules. The direct result of these experiments is the determination of the Hamiltonian interaction constants: $\frac{(1\ensuremath{-}{\ensuremath{\sigma}}_{J1})b}{{\ensuremath{\nu}}_{d}}$ equals 0.773527\ifmmode\pm\else\textpm\fi{}0.000016, ${c}_{p}$ is 85 600\ifmmode\pm\else\textpm\fi{}18 cps, ${c}_{d}$ equals 13 122\ifmmode\pm\else\textpm\fi{}11 cps, ${d}_{1}$ is 17 761\ifmmode\pm\else\textpm\fi{}12 cps, ${d}_{2}$ equals 22 454\ifmmode\pm\else\textpm\fi{}6 cps, and $\frac{f}{{H}^{2}}$ is (-26.90\ifmmode\pm\else\textpm\fi{}0.40)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}6}$ cps ${\mathrm{gauss}}^{\ensuremath{-}2}$. From these values of the interaction constants are derived the following physical quantities: the HD rotational magnetic moment $^{\mathrm{HD}}_{0}〈\frac{{\ensuremath{\mu}}_{J}}{J}〉_{1}$ equals 0.663211\ifmmode\pm\else\textpm\fi{}0.000014 nuclear magneton, the quadrupole moment $Q$ of the deuteron is (2.738\ifmmode\pm\else\textpm\fi{}0.014)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}27}$ ${\mathrm{cm}}^{2}$, the rotational magnetic field ${{H}_{p}}^{\ensuremath{'}}$ at the proton is 19.879\ifmmode\pm\else\textpm\fi{}0.006 gauss and ${{H}_{d}}^{\ensuremath{'}}$ at the deuteron is 20.020\ifmmode\pm\else\textpm\fi{}0.028 gauss, the internuclear spacing in the zeroth vibrational and first rotational state is such that $^{\mathrm{HD}}_{0}{〈{R}^{\ensuremath{-}3}〉}_{1}^{\ensuremath{-}\frac{1}{3}}$ equals (0.74604\ifmmode\pm\else\textpm\fi{}0.00010)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ cm, and the dependence of the diamagnetic susceptibility on molecular orientation (${\ensuremath{\xi}}_{\ifmmode\pm\else\textpm\fi{}1}\ensuremath{-}{\ensuremath{\xi}}_{0}$) is -(3.56\ifmmode\pm\else\textpm\fi{}0.20)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}31}$ erg ${\mathrm{gauss}}^{\ensuremath{-}2}$ ${\mathrm{molecule}}^{\ensuremath{-}1}$. Combining these values with Ramsey's theory on zero-point vibration and centrifugal stretching in molecules gives the high-frequency contribution to the molecular susceptibility, $^{\mathrm{HD}}_{0}〈{\ensuremath{\xi}}^{\mathrm{hf}}〉_{1}=(1.675\ifmmode\pm\else\textpm\fi{}0.005)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}31}$ erg ${\mathrm{gauss}}^{\ensuremath{-}2}$ ${\mathrm{molecule}}^{\ensuremath{-}1}$; the quadrupole moment of the electron distribution relative to the internuclear axis, $^{\mathrm{HD}}_{0}〈{Q}_{e}〉_{1}=(0.324\ifmmode\pm\else\textpm\fi{}0.010)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$; and the high-frequency contribution to the magnetic shielding constant for HD, $^{\mathrm{HD}}_{0}〈{\ensuremath{\sigma}}^{\mathrm{hf}}〉_{1}=(\ensuremath{-}0.594\ifmmode\pm\else\textpm\fi{}0.030)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}.$

The identification of a sharp low-wavelength cutoff in the spectrum of x rays emitted from deuterium discharges in Scylla has resulted in the assignment of an electron temperature of 240\ifmmode\pm\else\textpm\fi{}40 ev at the time of peak magnetic field compression. Simultaneous time-resolved absolute intensity determinations in the visible continuum, when coupled with the temperature measurement, yield an upper limit electron number density of (5\ifmmode\pm\else\textpm\fi{}1)\ifmmode\times\else\texttimes\fi{}${10}^{16}$/${\mathrm{cm}}^{3}$ at peak compression. The absolute value of $\frac{\mathrm{dE}}{d\ensuremath{\lambda}}$ in the soft x ray region is two hundred times larger than bremsstrahlung from a pure deuterium plasma at the temperature and density quoted, and it is postulated that the large experimental $\frac{\mathrm{dE}}{d\ensuremath{\lambda}}$ is the result of recombination radiation from about 2% of oxygen contaminant from the discharge tube walls.

The Scylla plasma experiment, which employs a rapidly rising magnetic field in a cylindrical mirror geometry to produce and heat a deuterium plasma, is described. Experimental studies of the reproducible neutron emission from the hot plasma show that the neutrons are emitted (1) in a symmetrical, bell-shaped time distribution centered on the maximum of the magnetic field, (2) from a limited region with a 2-cm axial length and a 1.5-cm diameter centered in the compression coil, and (3) in the radial direction with a narrow spread of energies and no significant anisotropy. The time distribution of the neutron emission is shown to be in agreement with a thermonuclear yield curve calculated for an adiabatic compression by the observed magnetic field. The neutron yield has been studied as a function of deuterium pressure, capacitor-bank voltage, and nitrogen impurity. Observations of the space-time distribution of the visible light emission with a streak camera show that (1) a strong radial "shock" occurs at the beginning of the second half-cycle, (2) very little light is emitted from the plasma "fireball" during the time of neutron emission, and (3) an intense luminous flux is produced during the later stages of the discharge. The energy absorbed in each half-cycle of the discharge by the gas is presented as calculated from the incremental damping of the driving magnetic field. Observations of hard x-ray emission (\ensuremath{\sim}200 kev) at times of maximum $\frac{\mathrm{dB}}{\mathrm{dt}}$ for operating pressures in the 5- to 50-micron range are contrasted with the characteristics of the neutron emission in regard to time distribution, pressure, impurities, and rf pre-excitation. Magnetic probe studies of the Scylla discharge are reported and evidence is given that the perturbing effects of the probe dominate the plasma temperature.

A diagnostic experiment has been carried out on the $d\ensuremath{-}d$ reactions produced by fast magnetic compression of a deuterium plasma. A determination of the velocity spectra of protons and of tritons from the $d\ensuremath{-}d$ reaction was made by magnetic analysis and nuclear plate detection of the particles. The observed distributions are Gaussian, with widths which correspond to a deuteron temperature of 1.3 kev. Comparison of the mean proton and triton momenta indicates that no plasma drift in the (axial) direction of observation is present, nor any potential difference between the source plasma and detector greater than a few volts. These results, coupled with previous ones on the neutron yield, duration, source extent, and lack of circumferential drift argue against any of the simple, physically plausible non-Maxwellian acceleration mechanisms for the $d\ensuremath{-}d$ reactions so far proposed.