Richard G. Fowler

Measured Lifetimes of Rotational and Vibrational Levels of Electronic States of N2

The lifetimes of vibrational levels of the B 3πg and C 3πu electronic states of molecular nitrogen and of the B 2Σu+ electronic states of the positive molecular nitrogen ion were measured by photometrically monitoring the excited level number densities in a pulsed invertron. Heavy‐particle pressure damping cross sections were obtained from experimental studies of the pressure dependence of the reciprocal lifetimes. Lifetimes of individual rotational levels from K = 14 to K = 35 of the B 2Σu+(υ = 0) levels were measured. The lifetimes of all rotational levels were identical. However, our results suggest a dependence of the line strength on the rotational level different from that predicted by the Born–Oppenheimer approximation with zero rotational–vibrational interaction and zero electron spin–rotational interactions.

Transition Probabilities for H2, D2, N2, N2+, and CO

The previously observed quenching of the a 3Σg+ state of the hydrogen molecule by neutral collision has been confirmed by a study of deuterium. Lifetimes have also been measured for what are believed to be the B 2Σu+ state of N2+; the C 3Πu state of N2; and the b 3Σ, d 3Π, and B 1Σ states of CO.

Theory of collision transfer of excitation in helium

Abstract A theory is presented to explain the multiple state mechanism for the transfer of excitation from singlet to triplet states in helium atoms proposed by St. John and Fowler. The spin-orbit interactions produce substantial singlettriplet mixing in the F states which is responsible for the transfer. It is shown that a helium atom in an n1P state, after colliding with a normal atom, transfers primarily into the “mixed” nF states which in turn cascade to 33D. The population of the 33D state is calculated as 4.0 × 105 atoms/cm3 as compared to 1.28 × 105 atoms/cm3 from experiment.

Radiative Lifetime of the B 2Σ+ State of CO+

The lifetime of the B 2Σ+ state of CO+ was measured by noting the decay time of 11 band heads of the (0, 0), (0, 1), (1, 0), and (1, 2) electronic–vibrational transitions of the Baldet–Johnson system. The lifetime exhibited no pressure dependence and no variation of the lifetime was noted for different rotational or vibrational levels. The lifetimes of the υ′ = 0 and υ′ = 1 states are 51.0 ± 0.7 and 52.2 ± 1.8 nsec, respectively. These lifetimes are in agreement with other recent measurements.

Burning‐Wave Speed Enhancement by Electric Fields

A significant relation has been observed between flame reaction rates and the intensity of an applied electric field in which the flame is immersed, which seems to establish the importance of electrons as reaction promoting agents.

Nature of Electron‐Fluid‐Dynamical Waves

A one‐dimensional, inviscid, multifluid model is employed to describe a constant velocity, steady‐profile, ionizing electron‐fluid‐dynamical wave propagating into a pure atomic gas subjected to an applied electric field E0. It is demonstrated that the electron‐fluid equations can be decoupled from the remaining equations allowing description of the wave in terms of electron variables only. Wave speed and resultant degree of ionization are derived as functions of applied field and initial gas pressure. Certain limiting conditions governing the existence of such steady‐profile waves and comparison with the experimental work on breakdown waves are also presented.

Electrons as a Shock Driver Gas

The electric shock tube, below a transition pressure characteristic of the tube diameter and the gas under study, exhibits two clearly distinguishable luminous fronts having the apparent attributes of shocks. The first front is initiated too quickly to be ascribed to a temperature increase of the gas molecules, and seems therefore to depend directly on the electrons and their fields in some way. It is hypothesized that electron pressure is the primary source of this motion. This hypothesis is consonant with the extensive evidence at hand.

The net-energy yield of nuclear power

Most prior net-energy studies of nuclear-power systems accounted only for the direct consumption of fuels and the indirect consumption of energy embodied in physical materials when making such estimates. Most ignored the energy embodied in labor, government, and financial services. In this study, total economic cost is used as a surrogate to estimate the total input-energy cost of constructing, operating, financing, and disposal of nuclear-power systems. Although the cost and performance data used in this study are from light-water reactor systems experience, it is assumed that fast-neutron reactors may be substituted for light-water reactors when economic conditions dictate. We make the conservative assumption that the cost and performance characteristics of fast-neutron reactors will be similar to those of light-water reactors. We conclude that the operation of a large nuclear-power system, involving a continuing construction program of starting one new 1000-MW system each month for 100 yrs, would yield a relatively small amount of net energy, under optimistic assumptions. Under less-optimistic assumptions the net-energy yield is negligible to negative. The average net-energy yield increases, somewhat, when optimistic assumptions are added to account for the possibility of improved efficiency in an all-electric economy.

ELECTRONS AS A HYDRODYNAMICAL FLUID

Publisher Summary This chapter describes the importance of electrons as a hydrodynamical fluid. The pressure of the electron component of plasma can exert a significant effect upon the mechanical behavior of the plasma. Because in the absence of currents the action of this pressure cannot be distinguished from that of any other component by the morphology of the effects, identification of its importance depends on measurements of the electron temperature or on a demonstration of the occurrence of the effect at an epoch when no other cause could as yet be active. When electron pressure is predominant, however, it represents a more efficient use of energy than otherwise, providing what amounts to an internal electronic and magnetic field (EMF) for the acceleration of the heavy ionic component. A strong magnetic field can coerce plasma into hydrodynamical motion. An idealized treatment of the magnetic action, based on an infinitely thin current shell advancing inwards and driving a shock wave which rebounds to reverse the advance of the layer, gave a reasonable qualitative agreement. It is suggested that the phenomenon of the striated positive column of the low pressure glow discharge certainly has a hydrodynamical basis, and probably bears the same relation to the ionic sound waves that forced oscillations do to free oscillations as the observed wave speeds are in the same range.

ELECTROMOTIVE FORCE IN A HIGHLY IONIZED PLASMA MOVING ACROSS A MAGNETIC FIELD

When a cloud of highly ionized gas flows across a magnetic field, an emf is produced in the gas which is proportional to the speed of flow. Oscillographic probe measurements have been carried out giving the flow speed as a function of position. By drawing currents from the probes the plasma resistance can be found at various distances from the plasma generator. The resistance is shown to be due to the motion of positive ions.