Multi-mode Alfv\'enic Fast Particle Transport and Losses: Numerical vs. Experimental Observation

In many discharges at ASDEX Upgrade fast particle losses can be observed due to Alfv\'enic gap modes, Reversed Shear Alfv\'en Eigenmodes or core-localized Beta Alfv\'en Eigenmodes. For the first time, simulations of experimental conditions in the ASDEX Upgrade fusion device are performed for different plasma equilibria (particularly for different, also non-monotonic q profiles). The numerical tool is the extended version of the HAGIS code [Pinches'98, Br\"udgam PhD Thesis, 2010], which also computes the particle motion in the vacuum region between vessel wall in addition to the internal plasma volume. For this work, a consistent fast particle distribution function was implemented to represent the strongly anisotropic fast particle population as generated by ICRH minority heating. Furthermore, HAGIS was extended to use more realistic eigenfunctions, calculated by the gyrokinetic eigenvalue solver LIGKA [Lauber'07]. The main aim of these simulations is to allow fast ion loss measurements to be interpreted with a theoretical basis. Fast particle losses are modeled and directly compared with experimental measurements [Garc\'ia-Mu\~noz'10]. The phase space distribution and the mode-correlation signature of the fast particle losses allows them to be characterized as prompt, resonant or diffusive (non-resonant). The experimental findings are reproduced numerically. It is found that a large number of diffuse losses occur in the lower energy range (at around 1/3 of the birth energy) particularly in multiple mode scenarios (with different mode frequencies), due to a phase space overlap of resonances leading to a so-called domino [Berk'95] transport process. In inverted q profile equilibria, the combination of radially extended global modes and large particle orbits leads to losses with energies down to 1/10th of the birth energy.Comment: 16 Pages, 17 Figure

Full-wave simulations of the O-X-B mode conversion in a realistic experimental geometry in the RFX-mod device

A full-wave code has been used to model the O–X–B mode-conversion process in RFX-mod. Parameter scans were performed to find the optimum launching condition for the microwave beam. Vacuum walls play an important role in the overall conversion efficiency, which is a key parameter for the success of the experiment. This is nicely illustrated in simulations

Il rischio cardiovascolare e la concentrazione plasmatica del colesterolo LDL: il ruolo dei Servizi Sanitari Regionali

Cardiovascular risk and increased plasma LDL cholesterol concentration: the role of the Regional Health ServiceThe relevance of hypercholesterolemia, as a risk factor for cardiovascular (CV) disease, requires urgent actions to detect and assist high-risk citizens/patients, thus reducing and/or avoiding future complications. This goal could be achieved through more widespread awareness of the problem within the Health System of the Veneto Region, joint efforts between clinical laboratories and clinicians in transmitting and interpreting informative laboratory reports, and deeper integration of hospital and community health services. Data from recent studies, recommendations of scientific societies and political-institutional guidelines helped in determining the number of patients in the Veneto Region, which may be suffering from clinical or biochemical conditions that impact on CV risk. These include hypercholesterolemia, which is particularly addressed in this paper, with special emphasis on FH (familial hypercholesterolemia), a chronic disease associated with very high CV risk

Simulations of combined ICRF and NBI heating for high fusion performance in JET

We report on simulations aimed at optimizing external heating using neutral beam injection (NBI) and radiofrequency waves in the ion cyclotron range of frequencies (ICRF) for high fusion yield in the JET tokamak. In this paper, D and DT plasmas are analyzed taking into account the NBI+RF synergy focusing on two different minority ICRF schemes, He and H, respectively. Our results show that by increasing external heating power to the maximum power available, the fusion neutron rate can be enhanced in D plasma by a factor of 2-3 with respect to our reference record D discharge. Regarding the DT plasma we present the external heating performance under the variation of key plasma parameters. We also study the impact of the effects of ICRH to the fusion yield and show that the ICRH power results in an enhanced fusion yield in the whole parameter space studied.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Dani Gallart would like to express his gratitude to “La Caixa” for support of his PhD studies.Postprint (author's final draft

Multi-strap in-port ICRF antenna modeling and development in support of ITER and EU-DEMO

Full-size 3D model of ITER ICRF antenna with 1D plasma electron density (ne) and 3D ne (from EMC3-Eirene) was simulated using the RAPLICASOL (COMSOL-based) code. Impedance matrices and coupled power agree well with TOPICA with 1D ne. Cases with 3D ne show port-to-port differences compared to 1D ne, as well as a lower (about 10%) coupled power. Efficient minimization of ITER antenna near-fields (to reduce RF sheaths by optimizing feeding) calculated by TOPICA and RAPLICASOL is possible with [0;π;π;0] (about balanced strap powers) and is even lower with [0;π;0;π] toroidal phasing (with dominant power from central straps). Lowest near-fields are with [0;π] poloidal phasing, but [0;-π/2] will be used in a load resilience setup with 3dB splitters. Under EUROfusion prospective research and development, in-port ICRF antenna concept for EU-DEMO with 8 quadruplets (4x toroidal by 2x poloidal) is considered to deliver 16.7 MW (3 antennas yielding 50 MW). Areas around the equatorial port and cut-ins in breeding blankets are used, with emphasis on [0;π;π;0] optimization. High-resolution RAPLICASOL calculations with full ne profile (without imposing a minimum ne value) shed light on field distribution with propagative slow wave in detailed antenna geometry

Characterization of 3-strap antennas in ASDEX Upgrade

The response of the local RF current measured at limiters of 3-strap ICRF antenna to variations of power balance and phasing at fICRF=30MHz agrees qualitatively well with EM calculations by TOPICA and RAPLICASOL codes. Measurements of tungsten sputtering yield and DC current at the limiters correlate strongly with the local RF current. In contrast to findings for the 2-strap antennas, values of DC current are predominantly positive, and negative only for some locations and feeding parameters. Explanations can involve more physical mechanisms than only parallel sheath dynamics

Recent progress on improving ICRF coupling and reducing RF-specific impurities in ASDEX Upgrade

The recent scientific research on ASDEX Upgrade (AUG) has greatly advanced solutions to two issues of Radio Frequency (RF) heating in the Ion Cyclotron Range of Frequencies (ICRF): (a) the coupling of ICRF power to the plasma is significantly improved by density tailoring with local gas puffing; (b) the release of RF-specific impurities is significantly reduced by minimizing the RF near field with 3-strap antennas. This paper summarizes the applied methods and reviews the associated achievements

Explanation of core ion cyclotron emission from beam-ion heated plasmas in ASDEX Upgrade by the magnetoacoustic cyclotron instability

Bursts of ion cyclotron emission (ICE), with spectral peaks corresponding to the hydrogen cyclotron harmonic frequencies in the plasma core are detected from helium plasmas heated by sub-Alfvénic beam-injected hydrogen ions in the ASDEX Upgrade tokamak. Based on the fast ion distribution function obtained from TRANSP/NUBEAM code, together with a linear analytical theory of the magnetoacoustic cyclotron instability (MCI), the growth rates of MCI could be calculated. In our theoretical and experimental studies, we found that the excitation mechanism of core ICE driven by sub-Alfvénic beam ions in ASDEX Upgrade is MCI as the time evolution of MCI growth rates is broadly consistent with measured ICE amplitudes. The MCI growth rate is very sensitive to the energy and velocity distribution of beam-injected ions and is suppressed by the slowing down of the dominant beam-injected ion velocity and the spreading of the fast ion distribution profile. This may help to account for the experimental observation that ICE signals disappear within ~3 ms after the NBI turn-off time, much faster than the slowing down times of the beam ions

EUROfusion Integrated Modelling (EU-IM) capabilities and selected physics applications

International audienceRecent developments and achievements of the EUROfusion Code Development for Integrated Modelling project (WPCD), which aim is to provide a validated integrated modelling suite for the simulation and prediction of complete plasma discharges in any tokamak, are presented. WPCD develops generic complex integrated simulations, workflows, for physics applications, using the standardized European Integrated Modelling (EU-IM) framework. Selected physics applications of EU-IM workflows are illustrated in this paper

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation