Electronic Excitation Of H2 By Electron Impact Using Soft Norm-conserving Pseudopotentials

We calculate electronic excitation cross sections for the b 3∑u + a 3∑g + c 3∏u, and d 3∏u states of H2 by electron impact. Our results were obtained with the Schwinger multichannel method with pseudopotentials and real potentials at the two-channel level of approximation. Pseudo-H atoms are used to generate H2 molecules with almost the same low-energy spectrum as the real molecules. We show that the dynamics of the electronic excitation process of the pseudomolecules by electron impact is very similar to the real case. Our results support the idea that pseudopotentials can be used to obtain reliable molecular electronic excitation cross sections by low-energy electron impact, confirming the expectations of previous studies with CH2O and HBr.54654355437Takatsuka, K., McKoy, V., (1981) Phys. Rev. A, 24, p. 2473(1984) Phys. Rev. A, 30, p. 1734Bettega, M.H.F., Ferreira, L.G., Lima, M.A.P., (1993) Phys. Rev. A, 47, p. 1111Natalense, A.P.P., Bettega, M.H.F., Ferreira, L.G., Lima, M.A.P., (1995) Phys. Rev. A, 52, pp. R1Bettega, M.H.F., Natalense, A.P.P., Lima, M.A.P., Ferreira, L.G., (1995) J. Chem. Phys., 103, p. 10566Rescigno, T.N., McCurdy, C.W., (1996) J. Chem. Phys., 104, p. 120Rescigno, T.N., (1996) J. Chem. Phys., 104, p. 125Hamann, D.R., Schlüter, M., Chiang, C., (1979) Phys. Rev. Lett., 43, p. 1494Christiansen, P.A., Lee, Y.S., Pitzer, K.S., (1979) J. Chem. Phys., 71, p. 4445Topp, W.C., Hopfield, J.J., (1973) Phys. Rev. B, 7, p. 1295Bachelet, G.B., Hamann, D.R., Schlüter, M., (1982) Phys. Rev. B, 26, p. 4199Bettega, M.H.F., Natalense, A.P.P., Lima, M.A.P., Ferreira, L.G., (1996) Int. J. Quantum Chem., 60, p. 821Goddard III, W.A., Hunt, W.J., (1974) Chem. Phys. Lett., 24, p. 464Kolos, W., Wolniewicz, L., (1965) J. Chem. Phys., 43, p. 2429Kolos, W., Wolniewicz, L., (1968) J. Chem. Phys., 48, p. 3672Browne, J.C., (1964) J. Chem. Phys., 40, p. 43Lee, M.T., Machado, L.E., Brescansin, L.M., Meneses, G.D., (1991) J. Phys. B, 24, p. 509Lima, M.A.P., Gibson, T.L., McKoy, V., Huo, W.M., (1988) Phys. Rev. A, 38, p. 4527. , and references cited therei

Strengthening altitude knowledge: a delphi study to define minimum knowledge of altitude illness for laypersons traveling to high altitude

Introduction: A lack of knowledge among laypersons about the hazards of high-altitude exposure contributes to morbidity and mortality from acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) among high-altitude travelers. There are guidelines regarding the recognition, prevention, and treatment of acute-altitude illness for experts, but essential knowledge for laypersons traveling to high altitudes has not been defined. We sought expert consensus on the essential knowledge required for people planning to travel to high altitudes. Methods: The Delphi method was used. The panel consisted of two moderators, a core expert group and a plenary expert group. The moderators made a preliminary list of statements defining the desired minimum knowledge for laypersons traveling to high altitudes, based on the relevant literature. These preliminary statements were then reviewed, supplemented, and modified by a core expert group. A list of 33 statements was then presented to a plenary group of experts in successive rounds. Results: It took three rounds to reach a consensus. Of the 10 core experts invited, 7 completed all the rounds. Of the 76 plenary experts, 41 (54%) participated in Round 1, and of these 41 a total of 32 (78%) experts completed all three rounds. The final list contained 28 statements in 5 categories (altitude physiology, sleeping at altitude, AMS, HACE, and HAPE). This list represents an expert consensus on the desired minimum knowledge for laypersons planning high-altitude travel. Conclusion: Using the Delphi method, the STrengthening Altitude Knowledge initiative yielded a set of 28 statements representing essential learning objectives for laypersons who plan to travel to high altitudes. This list could be used to develop educational interventions

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM