Soft skills

Here is the list of sample papers written for the Soft Skills Course in the 2014 Autumn Semester:

Diogo Aguiam Engineering basics of fusion plasmas reflectometry diagnostics  Reflectometry diagnostics use electromagnetic waves to measure the electron density profiles of plasmas, being used in fusion devices. The theory of electromagnetic wave propagation in plasmas is detailed for the case of ideal infinite plasmas and in the case of fusion plasmas, such as tokamak plasmas. The ordinary and extraordinary modes are explained and the ordinary mode is presented as the preferred, magnetic field independent mode for reflectometry diagnostics. The data processing mechanisms for the reconstruction of the density profile using an Abel inversion on the reflectometry interference data is presented. Experimental reflectometry results showing the time evolution of density profiles in the occurrence of ELMs are shown.
Norberto Catarino Oxidation behaviour of neutron irradiated Be pebbles  A Beryllium will be used as neutron multiplier material to increase the tritium breeding ratio (TBR) in fusion reactors. Since pure beryllium becomes brittle and swells under neutron irradiation we must understand its physical, chemical and mechanical evolution during irradiation. The chemical reactivity of beryllium is a factor of major concern since the oxidation of beryllium at temperatures above 800 °C can become an uncontrollable process. As the blanket of the fusion reactor will withstand temperatures in the 600 to 900 °C range it is crucial to understand the chemical behaviour of neutron-irradiated Beryllium under these conditions. In this work we present a detailed study of chemical composition and reactivity of Be pebbles after exposure to neutron irradiation, up to 3000appm He production, during the HIDOBE-01 campaign. The chemical composition of the irradiated samples was studied using ion beam analysis (IBA). Also the possible influence of the irradiation on the oxidation kinetics of Be was assessed. To get information on this issue some samples were oxidized at 700 °C under controlled air atmosphere (60% humidity) and a mixture of 40%N2 +60%O2. The thickness of the oxide layer was measured by Rutherford Backscattering Spectrometry (RBS) and the structural changes and surface morphology were followed by SEM. The results show the growth of a protective BeO layer indicating a diffusion mediated process following a parabolic law.
Jayanath CPK Laser-plasma ion acceleration and its applications  Laser plasma ion acceleration is an emerging area of research. The ions accelerated from laser plasma interactions are characterized by unique properties like high spatial quality and picoseconds time duration which makes them interesting for applications like proton radiography, cancer therapy, inertial confinement fusion, etc. There is a lot of interest in this area of research as the laser plasma ion accelerators can replace the conventional accelerators. A lot of studies has been already conducted in this area. This review discusses about the development in the field of laser plasma ion acceleration.
Ana Inês Dias Microwave plasmas applied to carbon nanostructure synthesis  In the present work, a microwave atmospheric plasmas driven by surface waves based method is used to generate different carbon nanostructures, as graphene sheets, nanotubes and nanospheres. The characterization of the samples produced was performed by Raman spectroscopy, scanning and transmission electron microscopy. Self-standing graphene sheets were synthesized with few layers (from one to five) which were confirmed by high resolution transmission electron microscopy as well as by the ratio of G and 2D peaks in Raman spectra analysis.
Susana Espinho Experimental investigation of vacuum ultraviolet emissions in microwave argon plasmas: dependence on microwave power and discharge pressure  Vacuum ultraviolet emission from argon wave driven microwave (2.45 GHz) plasmas operating at low pressures (0.2–1 mbar) has been investigated. The emitted spectra show the presence of argon atomic and ionic lines in the range 80–110 nm. The relative emission intensities of excited Ar atoms (at 104.8 nm and 106.6 nm) and ions (at 92.0 nm and 93.2 nm) were investigated as a function of the microwave power and pressure of the discharge. Both atomic and ionic emission lines increased linearly in intensity as the power was raised. Concerning the dependence on pressure, experimental results show that atomic and ionic lines decreased linearly in intensity as the pressure was increased. The plasma electron density was estimated to be in the order of 1012 cm-3.
João Loureiro Characterization of edge turbulent transport on COMPASS tokamak  Edge plasmas in the divertor configuration were studied on the COMPASS tokamak. The dependence of the decay length of the parallel heat flux q∥ was measured at different values of plasma current and line-averaged density. We have found that q∥ decreases with both the plasma current and the line-averaged density, which is in agreement with previous results achieved on the JET tokamak.
Syed Shah Variation of plasma resistivity during tokamak start-up  The variation of plasma resistivity, due to collisions, during TOKAMAK start-up is reviewed. For the breakdown phase, Townsend Avalanche model is used and for the Coulomb phase, Spitzer calculations are taken into account. Anisotropic nature of the plasma is discussed through the resistivity tensor. Finally, by modeling the TOKAMAK start-up as a low-pressure inductively coupled discharge, the variation in plasma resistivity is derived. It is found that the plasma resistivity varies directly with the square of the reflected impedance and inversely with the square of the mutual inductance and oscillating frequency of the primary circuit.
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