A two-year experimental campaign is described during which diamond-like carbon and plastic targets with thicknesses from 20 nanometers to 15 micrometers were irradiated by the Texas Petawatt Laser. Target composition and thickness were varied to modify the specifics of the laser-matter interaction. Plasma mirrors were selectively implemented to affect the contrast of the laser system and provide additional control of the physical processes under investigation. A number of particle diagnostics were implemented to measure the distribution of laser accelerated ions and electrons. In addition, optical diagnostics were fielded to measure the intensity profile of the laser and measure the density of the target pre-plasma. The results of these experiments suggest that the Texas Petawatt laser pulse has pre-pulse and pedestal features with intensities at least 10⁻⁸ of the main pulse. Micronscale targets were able to survive these features and maintain a relatively sharp density gradient until the arrival of the main laser pulse, allowing for ion acceleration. Electron spectra measured in this configuration show an average temperature of 10 MeV, with no v angular dependence out to at least 60 degrees. By contrast, interferometric plasma density measurements and a lack of any observable ion acceleration suggest that nanoscale targets were destroyed well before the main pulse. In this case, the peak of the laser pulse interacted with a cloud of plasma between 10⁻³ and 10⁻² of critical density. The contrast improvement offered by the implementation of plasma mirrors was seen to increase the maximum energy of laser accelerated protons from targets thicker than 1 micrometer. In addition, the plasma mirrors allowed nanoscale targets to survive pre-pulse and pedestal features and support the production of ion beams. Proton spectra show that ions were accelerated to greater maximum energies from nanoscale targets than from more traditional micron-scale targets. This effect can be attributed to a reduction in the target pre-plasma scale length upon the introduction of plasma mirrors. These results indicate that the manipulation of target properties and laser contrast can significantly affect the interaction between an ultrahigh intensity laser and a target. / text

In the past 30 years there has been a steady and growing appreciation in the literature of the importance and value of teachers' practical wisdom (TPW) - or phronesis as it is also known - to further an understanding of classroom practice and of the need to find ways to help teachers generate and share their perspectives with others. Nevertheless, the potential of this kind of knowledge (understood by Aristotle to be both practical and moral in its orientation) to contribute valuable insights to educational debates has still to be realised. Rather, educational decisions about policy and practice in many contexts (whether at a national or institutional level) are still largely driven by theoretical and technical knowledge perspectives and teacher practical wisdom perspectives are still often under-valued and remain under-represented in educational literature. One of the main reasons for this put forward in this thesis is the tendency in much of the literature to see this form of knowledge as classroom bound rather than to realise the ways in which it can inform broader pedagogical discussions. Bearing all of the above in mind, the aim of the study reported in this thesis into the TPW of 14 experienced expatriate English as a foreign language teachers (EEEFLTs) working in English language centres (ELCs) across the Kingdom of Saudi Arabia (KSA) is threefold. Its first aim is to provide a platform for the EEEFLTs to demonstrate the contribution their TPW can potentially make in addressing syllabus related issues in the KSA ELCs they have worked and, in doing so, show how the use of TPW is not confined to the classroom. Its second aim is to increase the visibility of the participants' TPW and thus raise awareness of the importance of research into TPW and to provide a model for how this can be conducted. The study's final aim is to provide a deeper understanding of the nature of TPW. Located in the interpretive paradigm, this study uses a TPW-friendly methodology to investigate TPW: interpretive phronetic educational research (IPER), which approaches and conducts educational research through a moral and practical problem-driven lens. This understanding drives the study's methodology and all stages of its data collection and analysis and the methods used in both. The goal of such methods is an epistemological one to generate TPW whilst empowering it also by highlighting its validity and how it is easily articulated - and thus captured - and not confined to the classroom. To assist with its articulation and capture, the study employs a process defined as Problematisation: a four-stage process consisting of reflection, problematisation, deliberation and articulation which drives and shapes the semi-structured interviews the study employs and the secondary research questions that inform the primary research question. The study concludes that the EEEFLTs use their TPW as a lens (that has 12 qualities) through which to view KSA ELC syllabi and, in doing so, identify many problems with the syllabi and subsequent consequences and suggest solutions to address both. These problems, consequences and solutions have been organised under six prominent categories that represent six main problem areas to emerge from the data that suggest the syllabi are teacher, textbook and test-centred, top-down, teacher-proof and time-driven. These categories represent six problem areas that in turn reflect the problematic, negative and disempowering context from which the data informing such categories and themes have been drawn. In this study, TPW is considered disempowered knowledge as a result of the disempowering context within which it has been acquired and is used. Previous TPW studies have been conducted in more positive settings and have perhaps for this reason not focused on TPW's disempowerment. In contrast, this study takes on a much more political role as it explores TPW's disempowerment in the KSA ELC context as well as in the broader context of academia and the literature. TPW's lack of visibility in TESOL and education has several implications because unless TPW achieves greater visibility, it may fade into extinction and its potential may never be realised. This study has been conducted in an attempt to prevent this happening.