High Energy K(alpha) Radiography Using High-intensity, Short-pulse Lasers

We have performed experiments using Callisto, the Vulcan 100 TW and the Vulcan Petawatt high intensity lasers to understand the characteristics of high energy, K{alpha} x-ray sources and to implement workable radiography solutions at 20-100 keV. Our measurements show that the K{alpha} size from a simple foil target is larger than 60 {micro}m, far larger than the experiment resolution requirement. The total K{alpha} yield is independent of target thicknesses verifying that refluxing plays a major role in photon generation. Smaller radiating volumes emit brighter K{alpha} radiation. 1-D radiography experiments using small-edge-on foils resolved 10 {micro}m features with high contrast. We tested a variety of small volume 2-D point sources such as cones, wires, and embedded wires, measuring photon yields and comparing our measurements with predictions from hybrid-PIC LSP simulations. In addition to high-energy, high-resolution backlighters, future experiments will also need imaging detectors and diagnostic tools that are workable in the 20-100 keV energy range. An initial look at some of these detector issues is also presented

Twenty-first-century International Political Economy: a class-relational perspective

The nature, subject matter and future direction of International Political Economy has been opened up for debate following interventions by Benjamin Cohen, John Hobson and special issues of the Review of International Political Economy and New Political Economy. Most contributors to the debate are dissatisfied with the current state of International Political Economy and desire to identify the ‘Big Questions’ of the 21st century. This article argues, however, that all contributors miss the ‘Really Big Question’ of the 21st century: the rise of a planetary labouring class of over 3 billion (and counting), living, for the most part, in poverty or near-poverty. While this class’s existence is not new (although its size is), International Political Economy’s ignorance of it is as old as the discipline’s institutional formation. This article shows that mainstream International Political Economy’s sidelining of class relations disables it from explaining the global systemic transformations that underpin changes in the relations between states and markets (International Political Economy’s traditional focus). It illustrates the long-term making of the global labouring class by discussing three examples of global systemic transformation: the rise of capitalism; the post-1945 embedded liberalism–development project conjuncture; and contemporary globalisation