bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear power and nuclear-weapons proliferation
Authors: Moniz Ernest J. , Neff Thomas L.
Published: April 2009

For decades, nuclear power has been considered a major component in the energy supply plans of some countries and an important option for the future in others. Like other energy sources, especially oil, nuclear power has become linked to national security and economic health in many countries; the magnitude of fuel reserves and the assurance of supply have become issues of intense international concern. However, nuclear power raises an additional issue: its potential for contributing to the acquisition of nuclear weapons by nations or even by terrorist groups. The goals of adequate energy supply and nuclear-weapons nonproliferation are therefore potentially in conflict.
NMR imaging technique provides high resolution
Authors: Lubkin Gloria B.
Published: April 2009

A new tool is being developed for producing two- and three-dimensional images of the distribution of material within an arbitrary object. Christened “zeugmatography” by Paul Lauterbur, one of the leaders in the field, the nuclear-magnetic-resonance technique generally involves applying an inhomogeneous magnetic field to spread out the nmr signal in space. Ultimately, one can then deduce the spatial distribution of material, either by mathematical or analog manipulations.
Laser heterodyne spectroscopy measures planetary winds
Authors: Lubkin Gloria B.
Published: April 2009

A new technique involving quantum electronics and lasers is being used for high-resolution astronomical observations. The technique—infrared heterodyne spectroscopy—has detected wind patterns on Venus to roughly 5 meters/sec (almost as good as the police do with radar detection of speeders). In addition, the technique has been used to detect such things as nonthermal emission from planets and the distribution of various gases in Earth's atmosphere.
Infrared-laser-induced unimolecular reactions
Authors: Bloembergen Nicolaas , Yablonovitch Eli
Published: April 2009

Photochemistry, which deals with the way in which chemical reactions are induced or altered by the presence of photons, has been a very active branch of science for many years. Although visible and ultraviolet photons, by giving rise to excited electronic states, have the most pronounced effects, much attention in recent years has gone to infrared photochemistry. Molecules irradiated with a powerful electromagnetic wave in the infrared remain in the electronic ground state (in the Born–Oppenheimer sense), but their vibrational modes may become highly excited. As a result, infrared-laser radiation often profoundly affects chemical reaction rates.
Quantum Electronics Conference meets in Atlanta
Authors: White Robin A.
Published: April 2009

The unofficial capital of the sunny “New South,” Atlanta, Georgia, will be the site for the Tenth International Quantum Electronics Conference with 24 sessions devoted to one of the “hottest” fields in physics. Scheduled to begin on Monday, 29 May and wind up on Thursday, 1 June, the Conference will meet at the Atlanta Hilton Hotel. The American Institute of Physics and the Institute of Electrical and Electronics Engineers are sponsoring the conference through their joint council on quantum electronics. Other co-sponsors of the conference are the International Union of Pure and Applied Physics and the European Physical Society through a joint council that includes the quantum electronics division of the EPS. Additionally, a concurrent conference on chemical and molecular lasers will be held as one of the scheduled sessions.
Josephson-junction logic and memory circuits
Authors: Lubkin Gloria B.
Published: April 2009

The superconducting tunnel effect predicted by Brian Josephson in 1962 is looking increasingly promising for another very practical application—as logic and memory circuits for computers. Josephson-junction circuits are capable of high switching speeds (50–100 picosec have already been obtained). And because such circuits operate at voltages comparable to the superconducting energy gap, the heat generated is typically microwatts, thousands of times lower than high-speed transistor circuits. The diminished heat-removal problem allows one to pack the Josephson circuits much closer than semiconductor circuits. Once high switching speeds are achieved, this packability becomes extremely important because then the major limitation on computer speed is how fast the electrical signal takes to move from one circuit to another.
Experimenters build detectors for PEP turn-on in 1979
Authors: Lubkin Gloria B.
Published: April 2009

Construction of the Positron–Electron Project at SLAC is in full swing, and the $78-million facility is expected to operate in October 1979. PEP will have 18-GeV positrons colliding with 18-GeV electrons in six interaction regions.
When is a particle?
Authors: Drell Sidney D.
Published: April 2009

Man's effort to understand what we and our world are made of is one of the greatest adventure stories of the human race. It dates from the beginning of recorded history. Science first flourished 2500 years ago with the quest of the early Greek philosophers for an underlying unity to the rich diversity observed in world around them. They realized that the search for an understanding of Nature at a fundamental level in terms of basic processes and constituents necessarily carried them beyond the sensory world of appearance.
Interacting-boson model emphasizes symmetry groups
Authors: Lubkin Gloria B.
Published: April 2009

Over the past few years a new model for even–even nuclei has been developed, in which one considers the nucleus as if it is made up of nucleon pairs that behave like bosons. Although many nuclear physicists were originally skeptical of the model, it is looking increasingly promising as some of its predictions are being experimentally observed. Recent attempts to establish a connection between the interacting-boson model and the microscopic behavior of nuclei are attracting attention, but the work is still controversial. Proponents of the theory think that they have already achieved a simple unified picture of several types of collective nuclear motion. They hope that their efforts will also lead to a unification of the collective and microscopic descriptions of nuclei. An important consequence of the model is that it predicts the presence of several kinds of dynamical symmetries in nuclei.
A peril and a hope
Authors: Weisskopf Victor F.
Published: April 2009

Forty years ago Otto Hahn and Fritz Strassmann discovered fission. The existence of this phenomenon could have been predicted before it was found if the theoretical physicists at that time had shown a little more inventiveness: It is a simple consequence of the facts that the Coulomb repulsion increases with the square of the number of protons and the nuclear attraction only with the first power. In 1938 enough was known about the nuclear force that it would not have been too hard to conclude that the nucleus must become unstable against a split in two parts around atomic number Z = 90.
Graphite intercalation compounds
Authors: Fischer John E. , Thompson Thomas E.
Published: April 2009

Solid-state physicists are turning more and more to complex synthetic materials in their search for novel phenomena and potentially useful properties. Many of these materials are highly anisotropic, so that interatomic interactions can for all practical purposes be neglected along one or two crystal axes. One of the oldest classes of prototype systems for exploring phenomena predicted to occur in two-dimensional systems are graphite intercalation compounds. These consist of stacks of one or more layers of hexagonally arrayed carbon atoms, alternating with monolayers of guest atoms or molecules. Striking changes in the properties of both host and guest result from intercalation. In addition to their quasi-two-dimensional behavior, fundamental interest centers on their variable anisotropy, which results from the fact that the strength of the interlayer interactions depends on the nature of the intercalated species.
Superfluid experiments support Kosterlitz–Thouless theory
Authors: Lubkin Gloria B.
Published: April 2009

Five years ago Michael Kosterlitz and David Thouless predicted that in the x–y or planar model of two-dimensional substances, a new type of phase transition would occur. In a two-dimensional superfluid, for example, at low temperatures the system would be arranged as bound vortex-antivortex pairs whose dissociation leads to the transition. More recently David Nelson and Kosterlitz suggested that the theory could be tested experimentally by looking for a universal jump in the superfluid density at the Kosterlitz–Thouless phase transition.
New data on two galaxies are consistent with black holes
Authors: Rothenberg Marian S.
Published: April 2009

How is energy supplied in the active centers of radio galaxies and quasars? This intriguing question lies at the heart of various overlapping and competing astrophysical theories, including those that propose the existence of a black hole. Now two separate sets of observations—of an apparent supermassive object at the center of galaxy M 87 and of a small narrow radio jet parallel to a much larger jet in NGC 6251—are being welcomed as a chance to test some of these ideas.
Parity nonconservation in neutral-current interactions
Authors: Lubkin Gloria B.
Published: April 2009

An experiment with polarized electrons at SLAC has found evidence for parity nonconservation in a neutral-current interaction. The observation offers strong support for the Weinberg–Salam gauge theory of the weak and electromagnetic interactions and removes the need for the more complicated gauge theories that have been developed since the original model by Steven Weinberg (Harvard University) and Abdus Salam (International Centre for Theoretical Physics) more than ten years ago.
Thirty years of fluid dynamics
Authors: Emrich Raymond J. , Frenkiel François N. , Dorfman J. Robert , Griffith Wayland C. , Veronis George
Published: April 2009

Interest in fluid dynamics as a separate field of physics with its own set of problems came about largely as a result of experiences during World War II. Until that time, the various events occurring in fluids were usually thought of as problems in mathematics or engineering. During the war years, however, the relations among phenomena such as turbulence, explosions, shock waves and supersonic aerodynamics were recognized, and physicists began to consider them again from the point of view of their own science. In 1947, the Division of Fluid Dynamics was established within The American Physical Society.
Two-dimensional metals are not truly metallic
Authors: Levi Barbara G.
Published: April 2009

When does a metal not act like one? When it is a two-dimensional thin film at 0 K. So says a recent theory by Elihu Abrahams (Rutgers), Philip W. Anderson (Princeton and Bell Labs), Donald C. Licciardello (Princeton) and T. V. Ramakrishnan (on leave at Princeton from the Indian Institute of Technology). Their surprising prediction that thin films never exhibit true metallic conductivity, and the renormalization-group scheme used to obtain this result, both created such a stir at the Gordon Conference on Quantum Liquids and Solids (held in July in Plymouth, N.H.) that next year's conference may be heavily devoted to this topic. The work of the Rutgers–Bell–Princeton team (since dubbed “the gang of four”) is a further realization of the ideas of David Thouless (Yale) who had predicted nonmetallic behavior at low temperatures for thin wires whose impurity resistances exceeded 10 kilo-ohms.
Proof-of-principle test for Elmo Bumpy Torus
Authors: Schwarzschild Bertram M.
Published: April 2009

We don't know whether he named it after St. Elmo's fire, or after his clever Uncle Elmo. Ray Dandl, who guided the evolution of the Elmo Bumpy Torus over the last two decades at the Oak Ridge National Laboratory, won't tell. The Elmo Bumpy Torus is something of a hybrid between toroidal and mirror fusion-reactor designs. Last October, a Department-of-Energy Concept Review Committee chose the EBT concept from among nine magnetic-confinement alternatives to tokamaks and mirrors, to be supported for a proof-of-principle test. Early this year the DOE Office of Energy Research concurred in the choice of the Elmo Bumpy Torus, and Oak Ridge is at present conducting a design competition among four industrial consortia for an EBT proof-of-principle facility, which is expected to be ready for experiments in about 1984. Aside from the Oak Ridge machine, the only other such bumpy torus currently in operation is in Japan.
High-capacity buried power lines
Authors: Schwarzschild Bertram M.
Published: April 2009

With the growth of metropolitan areas and their demand for electric power, it is becoming increasingly difficult to transport adequate electric power to such centers by conventional transmission lines. Several recent studies have concluded that by the end of the next decade it will be hard to make do without installing high-capacity underground cables to transport power to the central cities. Overhead lines are in many ways unacceptable in built-up areas, and conventional underground cables have insufficient carrying capacity.
A physicist in biomedical investigation
Authors: Yalow Rosalyn S.
Published: April 2009

What was involved in my transition from nuclear physicist to biomedical investigator and recipient of a Nobel Prize in Physiology or Medicine in 1977 for the development and application of radioimmunoassay? What is radioimmunoassay? In what way did physics have a role in the development of the concepts and methodology of radioimmunoassay? How did it begin?
Resonances in atoms and molecules
Authors: Biondi Manfred A. , Herzenberg Arvid , Kuyatt Chris E.
Published: April 2009

Observing resonances in cross-section-versus-energy curves has long been a way of life for nuclear and particle physicists, for whom this is often the only way to detect short-lived quantum states. Atomic physicists, on the other hand, have traditionally used other means for observing internal energy states of atoms and molecules. But sixteen years ago a resonance in the cross section for electrons scattering off helium changed the tradition, and by now there is a long catalog of observed resonances in atoms and molecules and an accompanying body of theoretical work that seeks to account for the newly discovered states and explain their behavior.
“Double quasar” could be gravity effect
Authors: von Foerster Thomas
Published: April 2009

Earlier this year observations of a close pair of visible astronomical sources previously identified with a quasar candidate from low-resolution radio data appeared to indicate that the pair is actually a single object doubled by the effect of a “gravitational lens.” More recent radio observations make some difficulties for the hypothesis, but do not necessarily rule it out. The exact nature of the object(s) is thus still uncertain.
Shiva moves closer to laser fusion
Authors: Schwarzschild Bertram M.
Published: April 2009

In recent months, the 20-armed Shiva laser system at the Lawrence Livermore Laboratory has attained a significant milestone on the road to the development of a laser-fusion reactor. The Livermore group has reported that with target pellets of classified design Shiva has driven the deuterium–tritium fuel inside the pellets to between 50 and 100 times its liquid density. (With unclassified ablative targets they report achieving 10 to 20 times liquid density.) One hundred times liquid density is only an order of magnitude short of the densities that will be needed to achieve “scientific break-even.” This goal, namely the release of as much fusion energy as the lasers deliver to the target (or the somewhat more modest goal of thermonuclear ignition), may well be achieved by Nova, the next generation laser system at Livermore, on which construction began in May.
Magnetite in bacteria linked to orientation
Authors: Levi Barbara G.
Published: April 2009

The birds and bees do it and—yes—even bacteria in the seas do it. Species of all these organisms synthesize tiny crystals of magnetite. The demonstration of a direct link between this magnetic material and an orientational response for at least the simplest of these organisms—bacteria—has suggested the tantalizing possibility that the magnetic material found in the abdomen of honey bees and near the skull of pigeons may play a similar guidance role. Recent studies on the bacteria have identified the magnetic particles as crystals of magnetite that fall in the narrow size range for single domains—an optimal configuration.
Microscience: an overview
Authors: Krumhansl James A. , Pao Yoh-Han
Published: April 2009

Just about twenty years ago, at the Christmas, 1959, meeting of The American Physical Society at Cal Tech, Richard P. Feynman gave a delightful talk, “There's Plenty of Room at the Bottom.” He said at first that he imagined that experimental physicists must often look with envy at men like Heike Kamerlingh Onnes, who opened the field of low temperatures, which seems to be bottomless—one can go down and down, or Percy Bridgman who, in designing a way to obtain high pressure, opened up another new field—in which one can go up and up. Attainment of ever higher vacuum, he said, was a continuing development of the same kind. He then went on to say that he wanted “to describe a field, in which little has been done, but in which an enormous amount can be done in principle.” This was the field of miniaturization, the problem of manipulating and controlling things on a small scale.
The National Submicron Facility
Authors: Wolf Edward D.
Published: April 2009

A field such as microstructure science, which draws its practitioners and their techniques from a wide range of disciplines, needs a national center where research workers from different backgrounds can come together, where appropriate experimental equipment can be concentrated, and which can serve as an information resource for the nation's research community. Without such a center for microstructure research, a very noticeable gap was opening up between university research on the one hand and the accomplishments of industrial laboratories on the other, due mainly to the expensive equipment and the interdisciplinary nature of microstructure science and engineering. The National Science Foundation, sensing the widening gap, established a national facility for university research in this field in 1977. Currently housed in temporary quarters at Cornell University, in Ithaca N.Y., the facility is due to move its operations to a new laboratory on the Cornell campus in 1981. The purpose of this “focussed” facility is to stimulate university research by providing an equipment base for visiting scientists from other universities, as well as for resident Cornell scientists, who could not otherwise afford programs in microstructure research.
High-resolution systems for microfabrication
Authors: Broers Alec N.
Published: April 2009

Extensive work on the fabrication of thin-film microstructures began in the early 1960's when it became apparent that thousands or even millions of circuits could potentially be integrated into a single piece of silicon less than a centimeter on a side. In the years since, the potential has been realized, as one can see from figure 1, and has produced the well-known dramatic growth of the microelectronics industry. The same technologies that make large-scale integrated circuits possible also make possible a variety of other devices of scientific and technological interest, including magnetic bubble devices, high-speed computer switching circuits based on the Josephson effect, surface acoustic-wave devices, integrated optical circuits, Josephson microbridges and zone-plate lenses for focusing soft x rays.
Microstructures and microelectronics
Authors: Moll John L. , Hammond Don
Published: April 2009

The scientific and technological achievements in the three decades following the invention of the transistor are unprecedented in the history of science. Accompanying and supporting this sparkling series of inventions and discoveries is a new industrial revolution that is still in the making. Microelectronics has achieved apparently miraculous results in both consumer and industrial products and services. A remarkable feature of these achievements has been that in almost every case, the microelectronic products have become steadily cheaper in an otherwise inflationary economy. Two major reasons for this deflationary effect are marketplace competition and the ever-increasing capability to produce microstructures. The ability to construct thousands of devices already connected in a digital circuit and to build the circuit in the area used for a single device a decade earlier (see, for example, figure 1) can serve as a general example of the effect of microstructure capability on microelectronics.
Nobel Prizes: to Glashow, Salam and Weinberg for Physics…
Authors: Lubkin Gloria B.
Published: April 2009

The 1979 Nobel prize in physics is to be awarded this month in Stockholm to Sheldon L. Glashow (Harvard University), Abdus Salam (International Centre for Theoretical Physics in Trieste and Imperial College, London) and Steven Weinberg (Harvard), “for their contribution to the theory of the unified weak and electromagnetic interaction between elementary particles, including inter alia the prediction of the weak neutral current.” The prize of about $190 000 is to be shared equally by the three theorists.
Structure of matter: A five-year outlook
Authors: Sachs Robert G.
Published: April 2009

What current and emerging problems of national significance can be identified through scientific research? What are the opportunities for, and constraints on, the use of new and existing scientific and technological capabilities toward a resolution of these problems?
DESY verifies two upsilon states; evidence for fifth quark
Authors: Lubkin Gloria B.
Published: April 2009

By stretching the energy limits of the DORIS storage ring to its fullest, experimenters at DESY in Hamburg have observed the upsilon and upsilon prime at roughly the masses reported in 1977 by Leon Lederman and his collaborators (PHYSICS TODAY, October 1977, page 17)—9.46 and 10.02 GeV/c2. But the new experiments have 20 times better energy resolution, primarily because they are done in an e+e− storage ring.
Satellite and Chilean telescopes correlate x-ray burst
Authors: von Foerster Thomas
Published: April 2009

Beginning in late 1975, astronomers have detected intense, brief, and often repetitive bursts of x rays from an ever-increasing number of pointlike sources. Recently a Harvard-MIT group reported observing an optical burst correlated with such an x-ray burst. Meanwhile, analysis of ten of the 30-odd known x-ray bursters has revealed a surprising degree of uniformity among them. Work on theoretical models is also proceeding, and at least one model has recently given good agreement with the observed properties of the bursters.
The physics of white dwarfs
Authors: Van Horn Hugh M.
Published: April 2009

White dwarf stars, so called because of the color of the first few to be discovered, occupy a key position in astrophysical theory. Together with neutron stars and black holes, they are the terminal points of stellar evolution. Their properties thus provide clues to the physical processes that take place during the rapid and often spectacular evolutionary stages near the ends of stellar lifetimes. In addition, white dwarfs provide astrophysical “laboratories” for “measuring” the physical properties of matter under extreme conditions. These extend from conditions like those in laser-produced plasmas to those typical of the solid crusts of neutron stars. White-dwarf stars also occur as components of cataclysmic binary systems—novae, dwarf novae and related objects—and knowledge of the properties of white dwarfs is essential to the development of satisfactory theoretical models for these systems.
Nuclear molecular resonances in heavy-ion collisions
Authors: Erb Karl A. , Bromley D. Allan
Published: April 2009

A significant trend within experimental nuclear physics over the past two decades has been the study, with ever-increasing precision, of the properties of nuclei under various extreme conditions. While such experiments have tended to bring the relatively unstructured many-body features of nuclear systems into the foreground, they have occasionally shown evidence of remarkably simple patterns of motion, even in situations differing drastically from those characterizing the nuclear ground state. We will here consider one such excitation, the quasimolecular mode, in which the nucleus appears to have the form of two smaller nuclei orbiting about each other.
Rochester operates user facility for laser fusion
Authors: Lubkin Gloria B.
Published: April 2009

The University of Rochester is now operating a National Users Laser Facility. Last October the first stage of the 30-terawatt Omega system, which uses neodymium glass, began experiments. This stage, known as Zeta, has six beams and delivers 3–4 TW peak power. In December the second stage, with 24 beams and 12–16 TW peak power, is expected to operate. Construction has been supported by DOE. The last stage, still not funded, is planned to reach 30–40 TW peak power (energy of 10 kJ) by the addition of 24 active-mirror booster systems. The pulse shape can be tailored, with the total pulse length between 0.05 and 1 nanosec.
Progress on deep-sea neutrino detection
Authors: Rothenberg Marian S.
Published: April 2009

For several summers, a group of physicists, astrophysicists and oceanographers interested in using the oceans to detect ultrahigh-energy cosmic-ray neutrinos have been meeting to exchange ideas. Their interest arises because clean seawater could provide the massive detector needed to observe low fluxes of weakly interacting, deeply penetrating neutrinos (PHYSICS TODAY, April 1976, page 18). The detector volume, about one cubic kilometer, located 5 km or so underwater, would avoid gross interference from ordinary cosmic rays. Organized as DUMAND (Deep Underseas Muon and Neutrino Detector), the group has been formulating the questions that would need to be answered in any feasibility study of the project. The most recent workshop took place 24 July–1 September at the Scripps Institution of Oceanography, La Jolla, with about 90 participants from the US, the Federal Republic of Germany, Japan and the Soviet Union.
NSF founds six regional instrumentation facilities
Authors: Lubkin Gloria B.
Published: April 2009

The National Science Foundation recently announced the establishment of Regional Instrumentation Facilities at six universities. The goal of the new program is to improve the quality and scope of research in various regions of the US by making sophisticated instrumentation and trained staff available. This fiscal year the program will receive $2.94 million from NSF and $500 000 from the Department of Energy.
Physics with polarized nuclei
Authors: Thompson William J. , Clegg Thomas B.
Published: April 2009

All those who wear Polaroid sunglasses are familiar with the polarization of light by reflection, a phenomenon first investigated by Etienne Malus in 1808 when he looked through a calcite crystal at the light reflected from the windows of the Palais Luxembourg. In 1921 Otto Stern and Walther Gerlach demonstrated the spin polarization of atomic beams in magnetic field gradients, and their methods are now in fairly widespread use.
Livermore constructs Mirror Fusion Test Facility
Authors: Levi Barbara G.
Published: April 2009

The Lawrence Livermore Laboratory has begun construction of its Mirror Fusion Test Facility, which is designed to investigate whether the plasma stability demonstrated in current experiments will continue (or even improve as predicted) on a larger scale. The $94-million effort reflects new confidence in the confinement of plasmas by magnetic mirrors, which is the primary alternative in the US magnetic-confinement program to the toroidal approach embodied by tokomaks. The confidence in mirrors stems partly from Livermore's success in controlling the growth of microinstabilities in their current 2XIIB device (see PHYSICS TODAY, November 1976, page 17). Hopes for the new machine are also based on the promising concepts of tandem mirrors and field reversal, either of which could further enhance the performance of the mirror fusion facility for the generation of power.
New NMR spectrometer doubles resolving power
Authors: Schwarzschild Bertram M.
Published: April 2009

A new, high-resolution, 600-MHz nuclear-magnetic-resonance spectrometer at Carnegie-Mellon University will be ready for experimenters early in the spring. With a magnetic field almost twice that of previously available NMR spectrometers, the new spectrometer provides roughly a doubling of resolving power for the study of organic molecules. The Carnegie-Mellon NMR Facility for Biomedical Studies (a joint undertaking of Carnegie-Mellon and the University of Pittsburgh) has called for proposals for a first round of short experiments covering a broad spectrum of applications, to explore the capabilities of the spectrometer.
Einstein the catalyst
Authors: Hoffmann Banesh
Published: April 2009

The celebrations held this year in honor of the centennial of Albert Einstein's birth will certainly bring forth lengthy discussions of his special and general theories of relativity and his contributions to quantum physics and other topics. This being so, I want to avoid what may prove to be beaten paths and to recall here instead an aspect of his work that may be overlooked in the torrent of reports and comments on his many achievements. That aspect is the effect of his style and his example on other major creative scientific figures, and, linked to this, his recognition of the merits of other people's seemingly bizarre ideas.
High-flux neutron source for fusion studies
Authors: Schwarzschild Bertram M.
Published: April 2009

In all of the fusion reactors currently under active consideration, an intense flux of 14-MeV neutrons will bombard the inner walls of the reactor. One expects a 14-MeV neutron flux of about 1014/cm2 sec. This is an order of magnitude below the typical flux in fission power reactors, but the much more energetic neutrons from the deuterium–tritium fusion reaction can generate significantly different kinds of damage to the materials of the reactor.
Fast ion beams reveal structures of molecular ions
Authors: Lubkin Gloria B.
Published: April 2009

Of the many ionic species that normally emerge from the ion source of an electrostatic accelerator, it has traditionally been only the monatomic ions that are considered to provide “useful” beams. The remaining beams of molecular ions (H2+, H3+, HeH+, OH+, etc.), which frequently constitute as much as 90% of the total ion-beam current, are seldom used in a nuclear-physics experiment.
Gravity waves slow binary pulsar
Authors: von Foerster Thomas
Published: April 2009

Although most physicists have long been convinced that gravity waves would ultimately be detected, there has yet been no unambiguous experimental confirmation of their existence. Recent work by Joseph Taylor and Lee Fowler of the University of Massachusetts at Amherst and Peter McCulloch of the University of Tasmania, however, provides further evidence for the reality of these elusive waves. In the 8 February issue of Nature (277, page 437), Taylor, Fowler and McCulloch report that the orbital period of the only known binary pulsar is diminishing at a rate of about 3 parts in 1012, which is consistent with quadrupole radiation of gravity waves by the system.
Recent progress in tokamak experiments
Authors: Murakami Masanori , Eubank Harold P.
Published: April 2009

At the 1968 conference on controlled fusion in Novosibirsk a group from Kurchatov, USSR, led by L. A. Artsimovitch, presented convincing evidence that one conceptually simple method for confining plasmas in a ring showed great promise for future developments. The name for their early machine, the tokamak, has now become the generic name for all such devices. The Russian successes led to a rapid expansion of research with tokamaks, so that while in 1968 there were only nine of them, all in the USSR, there are now more than a hundred; they are in the USSR, the US, Europe, Japan, and elsewhere.
Alternate concepts in magnetic fusion
Authors: Chen Francis F.
Published: April 2009

The tokamak is a marvelous device for plasma confinement, but can it be made into a commercially viable reactor? This is a question being asked more and more often by the electric utilities and the informed public. As a magnetic container of hot plasma, the tokamak is without peer. Now that the complicating factor of impurity radiation has been removed, the self-healing properties of the tokamak discharge, leading to good confinement scaling in both the collisional (MIT Alcator) and the collisionless (Princeton Large Torus) regimes, have become apparent. But satisfying the temperature, density and confinement time conditions for fusion is only a part of the story. The ultimate users of fusion—the electric utilities—are even more vitally interested in such factors as engineering feasibility, reliability and ease of maintenance, overall efficiency, total plant cost, small plant size, and safety and environmental impact. Since the tokamak was developed from the standpoint of plasma stability, there is concern that it may not be ideal from those other viewpoints. Indeed, there may be room for improvement in the accessibility allowed by a tight torus, in the high technology required for auxiliary heating, fueling, and treatment of wall surfaces, and in the costly equipment needed in breeding and containing tritium. Feasible solutions to these difficult engineering problems have been suggested—but are there better solutions?
Diagnostics for fusion experiments
Authors: Wharton Charles B.
Published: April 2009

Impressive advances have been reported in controlled fusion experiments during the past four years. Both open and closed confinement systems have performed up to expectations, rekindling the old optimism that has lain nearly dormant for 15 years. As a result, breakeven experiments are being proposed, designed and built in several laboratories.
Polymer expands 35% upon uv irradiation
Authors: Schwarzschild Bertram M.
Published: April 2009

When a collection of long polymeric molecules experiences a change of chemical environment, the system may under certain circumstances exhibit a contraction or dilation, sometimes generating considerable mechanical forces in the process. Such “mechanochemical” forces have in fact been put to work in an isothermal chemical engine invented by Aharon Katchalsky-Katzir and his colleagues at the Weizmann Institute in 1966. The original impetus for the study of mechanochemical phenomena in the early 1950's was an attempt to understand the mechanisms of muscle contraction.
Debate on SALT II
Authors: Panofsky W. K. H. , Teller Edward
Published: April 2009

SALT is a product of negotiation aimed at limiting strategic nuclear weapons spanning four administrations since 1967. Negotiations are not only across the table between the United States and the Soviet Union, but also involve resolutions of diverse positions at home on each side. Specifically, on the US side, SALT positions are the result of decisions by the President faced with inputs from the Defense Department, the Joint Chiefs of Staff, the Arms Control & Disarmament Agency, the CIA and the State Department. These decisions are also affected by consultation with Congressional leaders and with our Allies. One should be aware of this complex pattern to realize that the SALT outcome cannot make everyone happy. The negotiating history should be kept in mind when judging the sincerity of criticism that claims: “I support a SALT treaty but not this particular one.” Little purpose is served in discussing an “ideal” treaty that would be optimal only to a particular set of interests.
High-energy astronomers take a look at x-ray sky
Authors: von Foerster Thomas
Published: April 2009

The second orbiting High Energy Astronomy Observatory started its normal operations on 7 January. It has already produced more than a thousand x-ray images, many of them spectacular pictures of supernova remnants, quasars, galaxies, clusters of galaxies, stars and clusters of stars. It has also produced a number of puzzles, most notably for theories of pulsar formation.
Beauty and the quest for beauty in science
Authors: Chandrasekhar S.
Published: April 2009

The topic to which I have been asked to address myself is a difficult one, if one is to avoid the trivial and the banal. Besides, my knowledge and my experience, such as they are, compel me to limit myself, entirely, to the theoretical aspects of the physical sciences—limitations, most serious. I must, therefore, begin by asking for your patience and your forbearance.
The pseudopotential panacea
Authors: Cohen Marvin L.
Published: April 2009

Webster's dictionary defines panacea as a “remedy for all ills or difficulties; a cure-all.” A pseudopotential is an approximation to the real potential an electron feels in a solid. In what sense can it be called a cure-all? What are the ills it cures, the difficulties it overcomes or the problems it solves? And how does it help solve problems? Our object here will be to supply some answers to these questions and to describe the growing influence of theories involving pseudopotentials on solid state or condensed matter physics.
Puzzle of SS433: both a blue shift and a red shift
Authors: von Foerster Thomas
Published: April 2009

Recent observations confirm that a fourteenth-magnitude “peculiar” star in our galaxy is a bizarre object indeed, the like of which has not been seen before. Its spectrum exhibits hydrogen (Balmer) and helium emission lines with red and blue shifts indicating velocities up to 50 000 km/sec (0.17c), and these shifts vary roughly sinusoidally with a period of 164 days. The shifting lines are themselves comparatively narrow. The spectrum also contains unshifted hydrogen and helium lines.
Wiggler enhances SPEAR x-ray intensity
Authors: Schwarzschild Bertram M.
Published: April 2009

The first synchrotron-radiation beam emerging from the Stanford Synchrotron Radiation Laboratory's (SSRL) wiggler magnet was successfully steered into a newly completed experimental hall earlier this year, and it is now in regular operation during colliding-beam runs at the SPEAR electron-positron storage ring, in which the wiggler is installed. The wiggler shifts the synchrotron radiation spectrum emerging from SPEAR toward harder x rays and increases its overall intensity by about a factor of 6. Furthermore it makes a useful x-ray flux available even when SPEAR operates at low energy (<2.5 GeV), as it does 80% of the time. According to SSRL deputy director Herman Winick, these increases in available flux and time should do much to reduce the backlog of experimenters waiting to use SSRL beams for x-ray spectroscopy, biochemistry, crystallography and an increasing variety of other fields.
People and publishing in China
Authors: Koch H. William
Published: April 2009

The People's Republic of China, established by Mao Zedong in 1949, is the world's largest nation—900 million people—in an economy that is mainly agricultural and in which 80% of the people work on farms. It is a country of ancient tradition and enviable self-sufficiency that is reluctantly entering its industrial revolution. It is a country that US physicists and astronomers should attempt to understand as they establish channels of communications with the scientists of that country.
NRC panel examines need for high magnetic fields
Authors: Lubkin Gloria B.
Published: April 2009

Do we need higher magnetic-field facilities? That question is addressed in a recent report by a panel established by the Solid-State Sciences Committee of the National Research Council. The study was initiated at the behest of NSF, which supported the panel's efforts.
Solar photovoltaic energy
Authors: Ehrenreich Henry , Martin John H.
Published: April 2009

Although the Sun is frequently labeled as an “alternative” energy source, it has in fact produced almost all of man's energy throughout history. The world's energy economy now runs primarily on fossil fuels, a form of “solar capital” saved over geological time scales. Because this capital is apparently rather modest in amount and is not being renewed by nature at a rate comparable to our demands, we may eventually exhaust it. We will therefore be forced to turn either to the use of larger non-solar capital stocks such as primordial methane (if it exists), uranium-238 and deuterium, or to the use of regular “solar income” derived from the Sun's daily radiation.
Pyotr Kapitza, octogenarian dissident
Authors: Spruch Grace Marmor
Published: April 2009

Some years ago, at a Pugwash Conference, four of the five Soviet academicians present signed a condemnation of Andrei Sakharov for his political utterances. The fifth, Pyotr L. Kapitza, would not sign. Kapitza—the dean of Soviet science, winner of two Stalin prizes, four times awarded the Order of Lenin and last year awarded the Nobel Prize—had previously played Sakharov's role as the most outspoken Soviet scientist. In fact, he was also thought to have played Sakharov's role as father of the Soviet H bomb. Nobel Laureates are usually known solely for their work; a small number, however, are known as much for their personalities or the circumstances under which they worked. Kapitza is one of the latter. Most scientists have seen abstracts of his life, but few are familiar with the entire article.
Cosmology and elementary-particle physics
Authors: Turner Michael S. , Schramm David N.
Published: April 2009

Over the past decade or so, great progress has been made in two diverse areas of physics—cosmology and elementary-particle physics. In spite of the obvious differences of the two fields (figure 1), each has begun to illuminate the other, making interdisciplinary work involving them not only possible but even exciting. Thus, for example, the cosmological abundance of helium-4 fixes an upper limit of 8 on the number of quark varieties (“flavors”) in models that have a symmetry between quarks and leptons. And developments in the grand unified theories of elementary processes may resolve the puzzle of why there are roughly a billion photons for every baryon in the universe. As our knowledge of the fundamental particles and their interactions increases, and as our determination of cosmological observables improves (or new observables are discovered) the close relationship of these two disciplines promises to continue to be an exciting one.
SPEAR shows electron-muon pair produced unexpectedly
Authors: Lubkin Gloria B.
Published: April 2009

In a year full of surprises in high-energy physics, an experiment at the SPEAR colliding-electron-beam facility has uncovered yet another unexpected phenomenon: A significant number of events have been seen in which an electron and positron collide and produce one electron and one muon plus some missing energy. The experimenters can find no conventional explanation for this anomalous production of leptons and postulate that this reaction could proceed through the production of a pair of new particles. Each of the U particles, as they have been tentatively called, would then decay into an electron or a muon plus one or two neutrinos.
Fluorocarbons and the stratosphere
Authors: Lubkin Gloria B.
Published: April 2009

When the alarm was sounded last year that the ubiquitous fluorocarbon-propelled spray cans might be responsible for slowly removing Earth's protective ozone shield, reaction was widespread. Environmentalists urged an immediate ban, legislators held hearings and introduced legislation, government-sponsored study committees were formed, fluorocarbon-based industries defended their products and urged more definitive research (which they began to support in part). The concern, of course, is that the ozone layer shields life on Earth from harmful ultraviolet radiation. Much relevant research was already underway, sponsored by the Federal government, and by now workers in such disparate fields as atmospheric science, chemistry, physics and astronomy are working to answer the question, “Are the fluorocarbons depleting the ozone, and if so, how badly?”
Do young stars blow bubbles or dig tunnels as they age?
Authors: Leuchtag H. Richard
Published: April 2009

“Early type stars blow bubbles in the interstellar medium,” assert John Castor, Richard McCray and Robert Weaver of the Joint Institute for Laboratory Astrophysics and the University of Colorado in a recent paper in Astrophysical Journal Letters. These bubbles are seen as arising when the strong wind emanating from a star sweeps up the surrounding interstellar gas and compresses it into a shell. After a million years, such a bubble would have a radius of 30 parsec with a shell, about 4 pc thick, that expands at about 20 km/sec. While this theory is supported by a variety of observational data, it is being compared with an earlier theory postulating hot interstellar tunnels, which explains some of the same data—some of it apparently with greater accuracy.
Four new tokamaks will each try for a finite power output
Authors: Lubkin Gloria B.
Published: April 2009

The new generation of tokamak devices now being born is expected to produce a small net fusion power output. In Europe the site for the Joint European Torus has finally been selected after two years of wrangling among the members of the European Economic Community. The $210-million JET is to be built at the Culham Laboratory, near Oxford, England. In the US, ground-breaking ceremonies for the $239-million Tokamak Fusion Test Reactor were recently held at the Princeton Plasma Physics Laboratory. In Japan, construction of components is underway for the JT-60 device, to be built in a suburb of Tokyo still to be selected. The Soviet Union plans to build the largest member of the new tokamak generation, T-20, at a cost of about $500 million. The Soviets will emphasize a capability for breeding tritium and fissile materials in T-20, which might operate in the late 1980's. The other three are to operate earlier.
Anisotropy in blackbody radiation shows Earth's motion
Authors: Lubkin Gloria B.
Published: April 2009

Soon after the 3-K cosmic blackbody radiation was discovered, many wondered how isotropic the all-pervading radiation in fact was. Now a Princeton group reports that the radiation is isotropic to within 1 part in 1000 and a Berkeley group reports isotropy to 1 part in 3000. Furthermore, they both observe the motion of the Earth with respect to the radiation, so that one can tell how fast the Earth (or the Milky Way) is moving with respect to distant matter in the universe.
APS-AAPT meet in San Francisco
Authors: White Robin A.
Published: April 2009

San Francisco will host this year's joint annual meeting of The American Physical Society and the American Association of Physics Teachers. The sessions will take place Sunday through Thursday, 22–26 January 1978 at the San Francisco Hilton with auxiliary facilities at the Sir Francis Drake Hotel.
Argonne and others propose intense pulsed neutron source
Authors: Bennett Floyd C.
Published: April 2009

Development of an intense pulsed neutron source for solid-state physics research has been proposed by Argonne National Laboratory to the Energy Research and Development Administration. Meanwhile, scientists at Oak Ridge National Laboratory and Los Alamos Scientific Laboratory continue to examine their own facilities' advantages as source sites for neutron scattering studies.
Promising new results from Alcator
Authors: Lubkin Gloria B.
Published: April 2009

New results from the MIT tokamak caused quite a stir when they were reported at the APS plasma-physics division meeting in St. Petersburg, Florida in mid-November. The experiment, known as “Alcator,” achieved a value for the Lawson number, Nτ (where N is the peak particle density and τ is confinement time) greater than 1013 sec/cm3. This value for Nτ is five times greater than has been achieved in any other confinement experiment. It is generally believed that an Nτ of about 1014 sec/cm3 and an ion temperature of about 6 keV must be achieved to reach breakeven conditions for a fusion plasma.