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[en] For the past three months or so, Alberta has been in a situation where electricity prices are determined by market forces not regulation. The expected benefits of deregulation have not yet materialized as high power poll prices are the norm. Comparisons between Alberta and other jurisdictions operating under a regulated market should not be made. The authors argued that Alberta must act to develop significant additional generating resources to allow the growing needs to be met. Policymakers must work toward attracting private investment in new capacity using market means. The free market process cannot be perceived to be undermined by government. The development of forward markets and a market for ancillary services should be the priority in the coming months. The authors discussed investment under regulation, touching on depreciation and inflation, and the manner in which rates are affected by new investment. The next section covered the market since deregulation, explaining how the rise in prices is a reflection of the changing market conditions, the strong fundamentals and consumer protection. Some recommendations were made and the authors concluded that overall a very attractive market has been developed for Alberta. It involves a transparent design, relevant institutions and a large volume of information on the functioning of the market. 2 tabs., 2 figs
[en] The performance of Alberta's restructured electricity market was evaluated since its move to wholesale competition in January 2001. This paper presents the following eight conclusions that the authors arrived at following the evaluation: (1) To meet growing demand, the electricity prices in Alberta would have increased regardless of the type of environment (regulated or not). Capacity investment was required, and it was believed that moving to competition was the best way to attract investors. (2) Success in attracting private investment was attained as a result of Alberta's open market. It has restored reliability of supply and moderated prices. (3) Price comparisons must take into account what the prices would have been if the market had remained regulated. Due to unique generation costs and regulatory environments, comparisons with other regulated jurisdictions is inappropriate. (4) Convergence with other energy rates that would have been seen under regulation is being noted with respect to Alberta's market prices. (5) Under deregulation, prices increase according to the need for new investment and fall after the investment is made. Alberta has been on a path toward continued reduction in wholesale prices since 2001. (6) The non-price benefits of restructuring include improved generation efficiency, captured residual value from regulated assets, and shifting investment risk of new capacity additions from consumers to generators. (7) Downward pressure on prices was noted as a result of deregulation, as expected. (8) Significant value for consumers was captured through Alberta's restructuring process. 7 tabs., 7 figs
[en] A high-purity graphite probe for collecting impurities in ASDEX has been used for the first time. The probe head consists of a rotatable graphite cylinder housed in a fixed molybdenum shield containing an exposure slit. Measurements were made on the scrape-off layer plasma streaming to the upper outer divertor plate and, after extraction of the probe, collected impurities were identified and quantified using surface physics techniques. Single null ohmic discharges produce a threefold increase in erosion of the Cu plate of the active upper divertor compared to similar double null discharges. The radial distributions of scrape-off layer impurities change in both shape and intensity with vertical plasma position. Boronization of the main vessel reduces the amount of Fe collected by more than a factor of two but the oxygen deposit increases. Radial distributions of Cu and Fe deposits as a function of time for a neutral beam heated discharge are also discussed. (orig.)
[en] Impurity production and transport in ASDEX have been studied using a rotatable graphite collector probe which was exposed to the scrape-off layer plasma in the upper divertor chamber. Metallic deposits on the probe were later analysed using Rutherford backscattering spectroscopy and nuclear reaction analysis. Time resolved information (during tokamak discharges) and spatial profiles of collected impurity fluxes indicate strong erosion of the copper divertor plate during neutral beam heating of the plasma. Both stainless steel and copper deposits increase with neutral beam power. It is shown that, to a rough approximation, 0.2% of this auxiliary heating contributes to the increase in collected stainless steel impurities. Measurements made for single-null divertor discharges show that a copper flux of 6 x 1017 atoms s-1 is present in the scrape-off layer which is not directly sputtered from the target plates. Measurements made subsequent to boronization reveal significant long-term effect on the suppression of such impurities. (author)
[en] An experimental investigation of metallic impurities has been made in the ASDEX divertor in order to better understand their likely sources and production mechanisms. The impurities were collected on rotatable carbon collector strips which were exposed to the scrape-off layer plasma near the upper outer divertor plate under various discharge conditions. Quantitative ion beam analysis of exposed samples was subsequently carried out by Rutherford backscattering spectroscopy, proton induced X-ray emission and nuclear reaction spectroscopy. Time resolved measurements and spatial profiles of collected impurity fluxes reveal an increase in collected metallic impurities during auxiliary neutral beam heating of plasma discharges causing strong erosion of the copper divertor plate. To a rough approximation, 0.2% of this auxiliary heating power is invested in the production of stainless steel impurities. Measurements made for single-null divertor discharges show a copper flux of 6x1017 atoms·s-1 in the scrape-off layer which is not directly sputtered from the target plates. Collected impurity fluxes in the divertor chamber are found to increase with both the main plasma current and the density. Measurements made after boronization reveal an initial reduction in collected stainless steel impurities although boronization does not have any long term effect on the suppression of such impurities. Some limitations of the collector probe technique are also pointed out, and planned improvements of the existing setup are outlined. (author). 23 refs, 7 figs, 2 tabs
[en] Cu fluxes in the upper divertor of ASDEX have been measured with a collector probe. Experimental deposition profiles are compared with a two-dimensional computer model based on sputtering of divertor plate Cu by deuterium ions followed by ionisation of the Cu atoms in the divertor plasma and their redeposition onto the plate. Within the experimental uncertainties the profile shapes obtained for standard ohmic discharges were found to be in reasonable agreement. Measured value of Cu deposits were, however, much greater than model predictions. The results indicate that in order to better explain the collector probe measurements, the simple picture of Cu erosion and transport may need to be modified to take into account toroidal plasma asymmetries, sputtering contributions from impurity ions and additional Cu sources. Time resolved measurements on two discharges which were additionally heated by neutral beam injection and lower hybrid wave heating are also presented. (orig.)
[en] The parameters of the lowest 2S resonance state of the He− system were calculated using the Coulomb potential stabilization method. It was found that the errors of the resonance energy and width have the same character as that in the earlier studied two-electron systems H−, He, and Li+. It was shown that the errors can be minimized using a single-electron basis sets, which provides the best reproduction of the low-lying states of the helium atom.
[en] Present-day computational techniques provide a possibility of evaluating properties of macrosystems using ab initio quantum chemistry and theories of elementary processes. Physical and chemical phenomena on very different timescales have to be taken into account (excitation, emission, chemical reactions, diffusion) at different levels of refining. This refining covers a very wide region of parameters starting from the structure of species up to the macro chemical mechanism of their conversion. This multilevel approach is described in detail in the paper and includes interaction and data transfer between different levels of phenomena description. In the framework of the approach, unknown properties of molecules, ions and atoms (structure, potential energy curves, transition dipole moments) are calculated based on quantum-chemical methods. The calculation results are used to evaluate rate characteristics of physical and chemical processes. The developed kinetic state-to-state scheme is then used to calculate the macro properties of the system under investigation. As an example of the multilevel approach, the emission properties of the Ar-GaI3 positive column discharge plasma were calculated using the Chemical Work Bench computational environment. The calculations yield the electron energy balance and emission efficiency as functions of plasma parameters
[en] The DR theory of slow electrons with molecular ions in strong monochromatic light field is developed. The potential energy curves of the oxygen molecule O2** dissociative states are calculated. Classification of all possible transitions and reaction mechanisms are presented.
[en] A screening procedure is applied for several candidates (GaI_3, ZnI_2, SnI_2, InI, BiI_3, TlI) in respect of their light emission properties in a Ar–MeI_n glow discharge. Candidates are compared in terms of emission efficiency for a wide range of external conditions: temperature, matrix gas pressure, and MeI_n vapor pressure. The differences among the systems are explained by analyzing the kinetic mechanisms of formation, excitation, and loss of the emitting atoms. Analysis of the trends in the electronic structures of emitters (atoms) and precursors (molecules), as well as the stoichiometry and endothermicity of the plasma-chemical reactions, was made, and matched with selection rules. (paper)