Organisational geographies of power: Introduction to special issue

This paper introduces the special issue ‘organisational geographies of power’ by examining the theoretical and empirical context for debates. It does this, firstly, with reference to existing theoretical work on what power is and does as well as work on the construction of power relations. Building on this, the paper then, secondly, examines the way relational and production network approaches have incorporated power into work on transnational corporations before, thirdly, considering how work on neoliberalism has studied the construction of spatial power relations. In doing this the paper highlights four important questions for future research relating to the practices and spatiality of power, the exercising of power and the situated effects of power relations.     

Formation of episodic magnetically driven radiatively cooled plasma jets in the laboratory

We report on experiments in which magnetically driven radiatively cooled plasma jets were produced by a 1 MA, 250 ns current pulse on the MAGPIE pulsed power facility. The jets were driven by the pressure of a toroidal magnetic field in a “magnetic tower” jet configuration. This scenario is characterized by the formation of a magnetically collimated plasma jet on the axis of a magnetic “bubble”, confined by the ambient medium. The use of a radial metallic foil instead of the radial wire arrays employed in our previous work allows for the generation of episodic magnetic tower outflows which emerge periodically on timescales of ～30 ns. The subsequent magnetic bubbles propagate with velocities reaching ～300 km/s and interact with previous eruptions leading to the formation of shocks.     

The use of a towed side-scan sonar to investigate processes near the sea surface

Side-scan sonars directed upwards from beneath the sea surface have been towed in waters off the west coast of Scotland. The sonographs show echoes from targets identified as subsurface bubble clouds produced by breaking wind-waves. In some conditions organised patterns are seen in the bubble clouds and, in particular, bubbles are accumulated in parallel rows by the effect of Langmuir circulations. The sonar is useful as a diagnostic tool to recognise and quantify these dynamical processes in the upper ocean boundary layer.     

Radioactivity induced background noise in space-borne astronomical gamma-ray telescopes employing inorganic scintillation spectrometers

Based on monoenergetic proton beam tests of both NaI and CsI, a method for estimating the spallation background, due to the cosmic ray protons and trapped protons, has been developed. Comparisons between the calculated background noise and those measured by telescopes on board satellites are made. Good agreements of these comparisons demonstrate that the approach is capable of providing realistic estimates for specific space borne gamma-ray telescopes in well defined orbits.     

Rocket observations of middle latitude sporadic E, magnetic fields,winds and ionization

Two Skylark rockets carrying ion and R.F. electron probes, lithium and sodium vapourisers and proton precession magnetometers were launched from Woomera, Australia in November and December 1965 and made at least four encounters with sporadic E ionization. A magnetic field minimum was detected on only one of these encounters, and the minimum was found to be 2–3 km below the observed ion layer. The wind measurements deduced from observations of the vapour trails indicated that the sporadic E layer occurred in a region of ion divergence.     

Detection of past underground nuclear events by geochemical signatures in soils

This paper describes a research program to determine if a geochemical signature is retained in surface and sub-surface soils over a well-contained underground nuclear explosion. Samples of soil at surface and about 10–15 cm below were collected on orthogonal traverses up to about 1 km from ground zero (GZ, surface projection of blast point) at three locations in central (Ville) and southern Yucca Flat (Laredo and Presidio) on the Nevada Test Site (NTS). They were analyzed for total element content by instrumental neutron activation (INAA) and, using selective leaches, for partial element content, namely that amount bound to amorphous Fe oxyhydroxide and that amount bound to Mn oxide. Forty-two elements were determined in these leaches of both surface and sub-surface soils, by inductively coupled plasma mass spectrometry (ICP-MS), ICP emission spectrometry (ICP-ES) and hydride generation quartz tube atomic absorption spectrometry (HG-QTAAS). These partial leaches were chosen on the premise that the extreme temperature and pressure conditions created by an underground blast would volatilize elements in the surrounding rock and transport them along with fission products to the surface where they would be trapped by these phases in the soil. The INAA data generally show consistent concentrations of major, minor and trace elements within each location. In contrast, the selective leach data show distinct geochemical anomalies in numerous elements. Iodine, As, Mo, and U demonstrate particularly consistent positive anomalies at and around GZ at all three locations by both leaches. The amplitudes of these anomalies can exceed two orders of magnitude over background, particularly for I. This positive response is shown by more elements associated with Mn oxide than associated with Fe oxyhydroxide at all three locations; furthermore these patterns are more coherent and intense for some elements. The Mn oxide phase itself is more consistently distributed than is the Fe oxyhydroxide phase at the sites within each location. In most cases, significant depletion of Fe as amorphous Fe oxyhydroxide coincides with the multiple positive anomalies in this phase. The number and group of elements displaying distinct patterns is dependent upon the location as well as on the leach. The concentration ranges of elements extracted from the Fe oxyhydroxide or Mn oxide phase are similar for sites at Laredo and Presidio but dissimilar from those at Ville, probably a reflection of the differing geological settings. Whereas some anomalies are spatially quite compact, extending only about 50 m from GZ (e.g. Rb, Cs, Th), others such as I and Sb extend up to 300 m. The geochemical behaviour of the surface soil samples, although slightly noisier, is similar to that of the sub-surface suite. These results indicate that analysis of specific geochemical phases in soils over a suspected underground nuclear test has an important role in the on-site inspection component of the verification of the Comprehensive Test Ban Treaty.