Ignitor: Physics and Progress Towards Ignition

Thermonuclear ignition condition for deuterium-tritium plasmas can be achieved in compact, high magnetic field devices such as Ignitor. The main scientific goals, the underlying physics basis, and the most relevant engineering solutions of this experiment are described. Burning plasma conditions can be reached either with ohmic heating only or with small amount of auxiliary power in the form of ICRH waves, and this condition can be sustained for a time considerably longer than all the relevant plasma time scales. In the reference operating scenario, no transport barriers are present, and the resulting thermal loads on the plasma facing component are estimated to be rather modest, thanks to the high edge density and low edge temperature that ensure an effective intrinsic radiating mantle in elongated limiter configurations. Enhanced confinement regimes can also be obtained in configurations with double X-points near the first wall

Collective effects in spin polarized plasmas

A fusing plasma with coherently polarized spin nuclei can be subject to instabilities due to the anisotropy of the reaction product distributions in velocity space, which is a result of their polarization. The characteristics of these instabilities depend strongly on the plasma spatial inhomogeneities and a significant rate of spin depolarization can be produced by them if adequate fluctuation amplitudes are reached. The results of the relevant analysis are, in addition, of interest for plasma heating processes with frequencies in the range of the cyclotron frequencies of the considered nuclei

Information sharing and credit : firm-level evidence from transition countries

We investigate whether information sharing among banks has affected credit market performance in the transition countries of Eastern Europe and the former Soviet Union, using a large sample of firm-level data. Our estimates show that information sharing is associated with improved availability and lower cost of credit to firms. This correlation is stronger for opaque firms than transparent ones and stronger in countries with weak legal environments than in those with strong legal environments. In cross-sectional estimates, we control for variation in country-level aggregate variables that may affect credit, by examining the differential impact of information sharing across firm types. In panel estimates, we also control for the presence of unobserved heterogeneity at the firm level, as well as for changes in macroeconomic variables and the legal environment

Leading indicators of fiscal distress: evidence from extreme bounds analysis

Early warning systems (EWSs) are widely used to assess a country’s vulnerability to fiscal distress. A fiscal distress episode is identified as a period when government experiences extreme funding difficulties. Most EWSs employ a specific set of only fiscal leading indicators predetermined by the researchers, which casts doubt on their robustness. We revisit this issue using extreme bounds analysis, which allows identifying robust leading indicators of fiscal distress from a large set. A robust leading indicator’s effect does not strongly depend on the model specification. Consistent with the theoretical predictions of latest generation crisis models, we find that both fiscal and non-fiscal leading indicators are robust. In addition, we find that a fiscal vulnerability indicator based on fiscal and non-fiscal leading indicators offers a 29% gain in predictive power compared to a traditional one based only on fiscal leading indicators. This suggests that both fiscal and non-fiscal leading indicators should be taken into account when assessing country’s vulnerability to fiscal distress

Near term perspectives for fusion research and new contributions by the Ignitor program

The main advances made within the Ignitor program, that is aimed at investigating the physics of fusion burning plasmas near ignition, are described. In particular, the operation of the machine in the H and I regimes at the 10 MA plasma current levels has been considered and analyzed. The unique properties of the plasmas that can be generated by operating the machine with reduced parameters (lower magnetic fields and plasma currents) relative to those needed to achieve ignition are identified. A key feature of this operation is the relatively fast duty cycle that can be maintained. The Ideal Ignition Conditions, under which the density barrier due to bremsstrahlung emission in high density plasmas is removed, can be attained in this case. The plasma heating cycles are identified for which the contribution of ICRH is used both to enter the H-regime and to optimize the time needed for ignition. The on going effort to set up a test ICRH facility is described. The initial results (2 km/sec) of the high speed pellet injection system developed for Ignitor and operated at Oak Ridge are reported. The combined structural analysis and integration of the entire machine core (Load Assembly) is discussed. The adopted control system for both the machine and the plasma column has been designed and is described. The design solutions of the vertical field coils made of MgB2 and operating at 10 K have been identified and the relevant R&D program is underway. The analysis of the Caorso site and of its facility for the operation of the Ignitor with approved safety standards is completed. The relevant results are being made available for the operation of Ignitor at the Triniti site within the framework of the Italy-Russia agreement on the joint construction and operation of the Ignitor facility. A development effort concerning the advanced diagnostic systems that is being carried out for fusion burning plasma regimes is described. An initial analysis of the characteristics of a neutron source based on a system of Ignitor-like machines is reported

Macroeconomic Fluctuations, Inequality, and Human Development

This paper examines the two-way relationship between inequality and economic fluctuations, and the implications for human development. For years, the dominant paradigm in macroeconomics, which assumed that income distribution did not matter, at least for macroeconomic behavior, ignored inequality--both its role in causing crises and the effect of fluctuations in general, and crises in particular, on inequality. But the most recent financial crisis has shown the errors in this thinking, and these views are finally beginning to be questioned. Economists who had looked at the average equity of a homeowner--ignoring the distribution--felt comfortable that the economy could easily withstand a large fall in housing prices. When such a fall occurred, however, it had disastrous effects, because a large fraction of homeowners owed more on their homes than the value of the home, leading to waves of foreclosure and economic stress. Policy-makers and economists alike have begun to take note: inequality can contribute to volatility and the creation of crises, and volatility can contribute to inequality. Here, we explore the variety of channels through which inequality affects fluctuations and fluctuations affect inequality, and explore how some of the changes in our economy may have contributed to increased inequality and volatility both directly and indirectly. After describing the two-way relationship, the paper discusses hysteresis--the fact that the consequences of an economic downturn can be long-lived. Then, it examines how policy can either mitigate or exacerbate the inequality consequences of economic downturns, and shows how well-intentioned policies can sometimes be counterproductive. Finally, it links these issues to human development, especially in developing countries

Plasma Dynamics

Contains reports on five research projects.U.S. Air Force - Office of Scientifc Research (Contract AFOSR 84-0026)National Science Foundation (Grant ECS 85-14517)Lawrence Livermore National Laboratory (Subcontract 6264005)National Science Foundation (Grant ECS 85-15032)U.S. Department of Energy (Contract DE-ACO2-78-ET-51013)U.S. Department of Energy (Contract DE-ACO2-ET-51013

Plasma Dynamics

Contains table of contents for Section 2 and reports on four research projects.Lawrence Livermore National Laboratory Subcontract 6264005National Science Foundation Grant ECS 84-13173National Science Foundation Grant ECS 85-14517U.S. Air Force - Office of Scientific Research Contract AFOSR 89-0082-AU.S. Army - Harry Diamond Laboratories Contract DAAL02-86-C-0050U.S. Navy - Office of Naval Research Contract N00014-87-K-2001Lawrence Livermore National Laboratory Subcontract B108472National Science Foundation Grant ECS 88-22475U.S. Department of Energy Contract DE-FG02-91-ER-54109National Aeronautics and Space Administration Grant NAGW-2048U.S. Department of Energy Contract DE-AC02-ET-51013U.S. Department of Energy Contract DE-AC02-78-ET-5101