The European Physical Journal H最新文献

Fusion research was driven by the oil shocks in 1970’s and the concern about climate change during 20th century. This paper addressed the scientific research history of JT-60, the tokamak that achieved record fusion performances and opened the way toward the continuous operation of a tokamak fusion reactor through its scientific discoveries. The paper also highlighted technical struggles to improve machine capabilities and to solve technical issues faced during the JT-60 project. The missions of JT-60 were to achieve equivalent energy break-even (Q = P_DT^equi. / P_heat ≥ 1) and to establish a scientific basis for fusion reactor. The JT-60 made several modifications to reach equivalent break-even condition and continued efforts were made by the JT-60 team to solve critical technical issues during 23 years of research operation. Scientific success of JT-60 led to current ITER projects and the modification of JT-60 to a superconducting tokamak, JT-60SA. This paper is intended to be useful for the future researchers and managers of large-scale project by giving dynamical evolutions and highlighting key players. I dedicate this paper to Hiroshi Kishimoto, who made an outstanding contribution in managing the JT-60 research project.

This paper elucidates the close connections between hydrodynamic models of two-dimensional fluids and reduced models of plasma dynamics in the presence of a strong magnetic field. The key element is the similarity of the Coriolis force to the Lorentz force. The reduced plasma model, the Hasegawa–Mima equation, is equivalent to the two-dimensional ion vortex equation. The paper discusses the history of the Hasegawa–Mima model and that of a related reduced system called the Hasegawa–Wakatani model. The 2D fluid ? magnetized plasma analogy is exploited to argue that magnetized plasma turbulence exhibits a dual cascade, including an inverse cascade of energy. Generation of ordered mesoscopic flows in plasmas (akin to zonal jets) is also explained. The paper concludes with a brief explanation of the relevance of the quasi-2D dynamics to aspects of plasma confinement physics.

This oral history interview presents Roald Z. Sagdeev’s story of plasma physics in Russia. It chronicles the Russian school’s achievements in basic, laboratory, fusion and space plasma physics. The interview begins with memories of Sagdeev’s graduate student days in Moscow and then describes his work at the Kurchatov Institute of Atomic Energy (1956–1961), the Budker Institute of Nuclear Physics in Novosibirsk (1961–1971) and the Space Research Institute (IKI) (1973–1988). The interview examines the development of quasilinear theory, collisionless shocks, wave turbulence, instabilities, drift waves, chaos theory, the early stages of magnetic confinement theory and space plasma physics. Sagdeev and his school made seminal contributions in all of these areas, and all are central topics in plasma physics today. Sagdeev also speaks of his collaborations and friendships with notable scientists, such as M.N. Rosenbluth, M.A. Leontovich, L.A. Artisimovich, L.I. Rudakov, A.A. Galeev, V.E. Zakharov, as well as of the political and institutional challenges of this period. The conversation reflects Sagdeev’s unique and significant influence in modern plasma theory, Russian space exploration and his support of international cooperation for the advancement of humanity.

The two main methodologies of computational Statistical Mechanics, namely the stochastic Monte Carlo and the deterministic Molecular Dynamic methods, were developed in the USA in the mid 1950’s. In the present paper we show how these “computer experiments” migrated to Europe in the 60s, and first bloomed at the Orsay Science Faculty, before spreading throughout Europe. Collaborations between the Orsay group, led by Loup Verlet, and pioneering groups in the USA and Europe are pointed out. Finally it is shown how the celebrated Verlet algorithm for the integration of classical equations of motion can be traced back to Isaac Newton.

The paper traces the early stages of Berni Alder’s scientific accomplishments, focusing on his contributions to the development of Computational Methods for the study of Statistical Mechanics. Following attempts in the early 50s to implement Monte Carlo methods to study equilibrium properties of many-body systems, Alder developed in collaboration with Tom Wainwright the Molecular Dynamics approach as an alternative tool to Monte Carlo, allowing to extend simulation techniques to non-equilibrium properties. This led to the confirmation of the existence of a phase transition in a system of hard spheres in the late 50s, and was followed by the discovery of the unexpected long-time tail in the correlation function about a decade later. In the late 70s Alder was among the pioneers of the extension of Computer Simulation techniques to Quantum problems. Centered around Alder’s own pioneering contributions, the paper covers about thirty years of developments in Molecular Simulation, from the birth of the field to its coming of age as a self-sustained discipline.

I summarize, at its 41st – and what would have been Bruno Zumino’s 94th – birthday, the history of the discoveries of Supergravity, and some of its structure and later developments.

The cosmological constant was proposed 100 years ago in order to make the model of static Universe, imagined then by most scientists, possible. Today it is the main candidate for the physical essence causing the observed accelerated expansion of our Universe. But, as well as a hundred years ago, its nature is unknown. This paper is devoted to the story of invention of Λ by Albert Einstein in 1917, rejection of it by him in 1931 and returning of it into the great science by other scientists during the century. The aim is to once again emphasize prominent role of cosmological constant in the development of ideas of modern physics and cosmology, focusing on the main points and publications, the choice of which may have a certain part of subjectivity.

We provide an account of John Wheeler’s transition from his work on elementary particle physics (in which particles provided the ultimate ontology in his worldview), to his work on gravitation and general relativity (in which spacetime geometry was the ultimate object out of which all other things were composed). We also describe his early work on quantum gravity largely as a long-standing attempt to derive the elementary particles from spacetime structure.

Evidence that a model of hard spheres exhibits a first-order solid-fluid phase transition was provided in the late fifties by two new numerical techniques known as Monte Carlo and Molecular Dynamics. This result can be considered as the starting point of computational statistical mechanics: at the time, it was a confirmation of a counter-intuitive (and controversial) theoretical prediction by J. Kirkwood. It necessitated an intensive collaboration between the Los Alamos team, with Bill Wood developing the Monte Carlo approach, and the Livermore group, where Berni Alder was inventing Molecular Dynamics. This article tells how it happened.

The main purpose of this paper is to analyse the earliest work of Léon Rosenfeld, one of the pioneers in the search of Quantum Gravity, the supposed theory unifying quantum theory and general relativity. We describe how and why Rosenfeld tried to face this problem in 1927, analysing the role of his mentors: Oskar Klein, Louis de Broglie and Théophile De Donder. Rosenfeld asked himself how quantum mechanics should concretely modify general relativity. In the context of a five-dimensional theory, Rosenfeld tried to construct a unifying framework for the gravitational and electromagnetic interaction and wave mechanics. Using a sort of “general relativistic quantum mechanics” Rosenfeld introduced a wave equation on a curved background. He investigated the metric created by what he called ‘quantum phenomena’, represented by wave functions. Rosenfeld integrated Einstein equations in the weak field limit, with wave functions as source of the gravitational field. The author performed a sort of semi-classical approximation obtaining at the first order the Reissner-Nordstr?m metric. We analyse how Rosenfeld’s work is part of the history of Quantum Mechanics, because in his investigation Rosenfeld was guided by Bohr’s correspondence principle. Finally we briefly discuss how his contribution is connected with the task of finding out which metric can be generated by a quantum field, a problem that quantum field theory on curved backgrounds will start to address 35 years later.