| 1. |
- Kim, Hyun-Tae, et al.
(författare)
-
Validation of D-T fusion power prediction capability against 2021 JET D-T experiments
- 2023
-
Ingår i: Nuclear Fusion. - 0029-5515 .- 1741-4326. ; 63:11
-
Tidskriftsartikel (refereegranskat)abstract
- JET experiments using the fuel mixture envisaged for fusion power plants, deuterium and tritium (D-T), provide a unique opportunity to validate existing D-T fusion power prediction capabilities in support of future device design and operation preparation. The 2021 JET D-T experimental campaign has achieved D-T fusion powers sustained over 5 s in ITER-relevant conditions i.e. operation with the baseline or hybrid scenario in the full metallic wall. In preparation of the 2021 JET D-T experimental campaign, extensive D-T predictive modelling was carried out with several assumptions based on D discharges. To improve the validity of ITER D-T predictive modelling in the future, it is important to use the input data measured from 2021 JET D-T discharges in the present core predictive modelling, and to specify the accuracy of the D-T fusion power prediction in comparison with the experiments. This paper reports on the validation of the core integrated modelling with TRANSP, JINTRAC, and ETS coupled with a quasilinear turbulent transport model (Trapped Gyro Landau Fluid or QualLiKiz) against the measured data in 2021 JET D-T discharges. Detailed simulation settings and the heating and transport models used are described. The D-T fusion power calculated with the interpretive TRANSP runs for 38 D-T discharges (12 baseline and 26 hybrid discharges) reproduced the measured values within 20 % . This indicates the additional uncertainties, that could result from the measurement error bars in kinetic profiles, impurity contents and neutron rates, and also from the beam-thermal fusion reaction modelling, are less than 20 % in total. The good statistical agreement confirms that we have the capability to accurately calculate the D-T fusion power if correct kinetic profiles are predicted, and indicates that any larger deviation of the D-T fusion power prediction from the measured fusion power could be attributed to the deviation of the predicted kinetic profiles from the measured kinetic profiles in these plasma scenarios. Without any posterior adjustment of the simulation settings, the ratio of predicted D-T fusion power to the measured fusion power was found as 65%-96% for the D-T baseline and 81%-97% for D-T hybrid discharge. Possible reasons for the lower D-T prediction are discussed and future works to improve the fusion power prediction capability are suggested. The D-T predictive modelling results have also been compared to the predictive modelling of the counterpart D discharges, where the key engineering parameters are similar. Features in the predicted kinetic profiles of D-T discharges such as underprediction of ne are also found in the prediction results of the counterpart D discharges, and it leads to similar levels of the normalized neutron rate prediction between the modelling results of D-T and the counterpart D discharges. This implies that the credibility of D-T fusion power prediction could be a priori estimated by the prediction quality of the preparatory D discharges, which will be attempted before actual D-T experiments.
|
|
| 2. |
- Murphy, B. F., et al.
(författare)
-
Femtosecond X-ray-induced explosion of C-60 at extreme intensity
- 2014
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Understanding molecular femtosecond dynamics under intense X-ray exposure is critical to progress in biomolecular imaging and matter under extreme conditions. Imaging viruses and proteins at an atomic spatial scale and on the time scale of atomic motion requires rigorous, quantitative understanding of dynamical effects of intense X-ray exposure. Here we present an experimental and theoretical study of C-60 molecules interacting with intense X-ray pulses from a free-electron laser, revealing the influence of processes not previously reported. Our work illustrates the successful use of classical mechanics to describe all moving particles in C-60, an approach that scales well to larger systems, for example, biomolecules. Comparisons of the model with experimental data on C-60 ion fragmentation show excellent agreement under a variety of laser conditions. The results indicate that this modelling is applicable for X-ray interactions with any extended system, even at higher X-ray dose rates expected with future light sources.
|
|
| 3. |
- Bielecki, Johan, 1982, et al.
(författare)
-
Electrospray sample injection for single-particle imaging with x-ray lasers
- 2019
-
Ingår i: Science advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 5:5
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility of imaging single proteins constitutes an exciting challenge for x-ray lasers. Despite encouraging results on large particles, imaging small particles has proven to be difficult for two reasons: not quite high enough pulse intensity from currently available x-ray lasers and, as we demonstrate here, contamination of the aerosolized molecules by nonvolatile contaminants in the solution. The amount of contamination on the sample depends on the initial droplet size during aerosolization. Here, we show that, with our electrospray injector, we can decrease the size of aerosol droplets and demonstrate virtually contaminant-free sample delivery of organelles, small virions, and proteins. The results presented here, together with the increased performance of next-generation x-ray lasers, constitute an important stepping stone toward the ultimate goal of protein structure determination from imaging at room temperature and high temporal resolution.
|
|
| 4. |
- Larsson, Mats, et al.
(författare)
-
Double core-hole formation in small molecules at the LCLS free electron laser
- 2013
-
Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16, s. 164030-
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated nonlinear processes in small molecules by x-ray photoelectron spectroscopy using the Linac Coherent Light Source free electron laser, and by simulations. The main focus of the experiments was the formation of the two-site double core-hole (tsDCH) states in the molecules CO2, N2O and N-2. These experiments are described in detail and the results are compared with simulations of the photoelectron spectra. The double core-hole states, and in particular the tsDCH states, have been predicted to be highly sensitive to the chemical environment. The theory behind this chemical sensitivity is validated by the experiments. Furthermore, our simulations of the relative integrated intensities of the peaks associated with the nonlinear processes show that this type of simulation, in combination with experimental data, provides a useful tool for estimating the duration of ultra-short x-ray pulses.
|
|
| 5. |
- Sanchez-Gonzalez, A., et al.
(författare)
-
Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL
- 2015
-
Ingår i: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 48:23
-
Tidskriftsartikel (refereegranskat)abstract
- We report the first measurement of the near oxygen K-edge auger spectrum of the glycine molecule. Our work employed an x-ray free electron laser as the photon source operated with input photon energies tunable between 527 and 547 eV. Complete electron spectra were recorded at each photon energy in the tuning range, revealing resonant and non-resonant auger structures. Finally ab initio theoretical predictions are compared with the measured above the edge auger spectrum and an assignment of auger decay channels is performed.
|
|
| 6. |
- Zhaunerchyk, Vitali, et al.
(författare)
-
Disentangling formation of multiple-core holes in aminophenol molecules exposed to bright X-FEL radiation
- 2015
-
Ingår i: Journal of Physics B. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 48:24
-
Tidskriftsartikel (refereegranskat)abstract
- Competing multi-photon ionization processes, some leading to the formation of double core hole states, have been examined in 4-aminophenol. The experiments used the linac coherent light source (LCLS) x-ray free electron laser, in combination with a time-of-flight magnetic bottle electron spectrometer and the correlation analysis method of covariance mapping. The results imply that 4-aminophenol molecules exposed to the focused x-ray pulses of the LCLS sequentially absorb more than two x-ray photons, resulting in the formation of multiple core holes as well as in the sequential removal of photoelectrons and Auger electrons (so-called PAPA sequences).
|
|
| 7. |
- Barillot, T., et al.
(författare)
-
Correlation-Driven Transient Hole Dynamics Resolved in Space and Time in the Isopropanol Molecule
- 2021
-
Ingår i: Physical Review X. - : American Physical Society. - 2160-3308. ; 11:3
-
Tidskriftsartikel (refereegranskat)abstract
- The possibility of suddenly ionized molecules undergoing extremely fast electron hole (or hole) dynamics prior to significant structural change was first recognized more than 20 years ago and termed charge migration. The accurate probing of ultrafast electron hole dynamics requires measurements that have both sufficient temporal resolution and can detect the localization of a specific hole within the molecule. We report an investigation of the dynamics of inner valence hole states in isopropanol where we use an x-ray pump-x-ray probe experiment, with site and state-specific probing of a transient hole state localized near the oxygen atom in the molecule, together with an ab initio theoretical treatment. We record the signature of transient hole dynamics and make the first tentative observation of dynamics driven by frustrated Auger-Meitner transitions. We verify that the effective hole lifetime is consistent with our theoretical prediction. This state-specific measurement paves the way to widespread application for observations of transient hole dynamics localized in space and time in molecules and thus to charge transfer phenomena that are fundamental in chemical and material physics.
|
|
| 8. |
- Bolognesi, P., et al.
(författare)
-
A study of the dynamical energy flow in uracil
- 2015
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 635
-
Tidskriftsartikel (refereegranskat)abstract
- The time resolved photoionization of C 1s in uracil following excitation of the neutral molecule by 260 nm pulses has been studied at LCLS.
|
|
| 9. |
- Fang, L., et al.
(författare)
-
Multiple Ionization and Double Core-hole Production in Molecules using the LCLS X-ray FEL
- 2012
-
Ingår i: Journal of Physics, Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 388:3, s. 032028-
-
Tidskriftsartikel (refereegranskat)abstract
- We used the world's first hard x-ray FEL to investigate the response of molecular systems to the ultra-intense, femtosecond x-ray radiation. We report sequential multiphoton ionization, frustrated absorption and double core hole production mechanisms.
|
|
| 10. |
- Sahlén, Martin, et al.
(författare)
-
Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-Ray Free-Electron Laser
- 2012
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 108:15, s. 153003-
-
Tidskriftsartikel (refereegranskat)abstract
- We have performed x-ray two-photon photoelectron spectroscopy using the Linac Coherent Light Source x-ray free-electron laser in order to study double core-hole (DCH) states of CO2, N2O, and N-2. The experiment verifies the theory behind the chemical sensitivity of two-site DCH states by comparing a set of small molecules with respect to the energy shift of the two-site DCH state and by extracting the relevant parameters from this shift.
|
|
