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The 5D and 6D Monte-Carlo code MCGO [1] has been recently upgraded with an RF kick operator based on full wave fields from AORSA, and was tested against CQL3D in a scenario of minority ICRH in C-Mod [2]. The operator utilizes local quasilinear diffusion coefficients that include all components of RF electric field and all-orders terms for finite Larmor radius effects. The RF operator acts on both perpendicular and parallel components of particle momentum. In the present study, the simulations are performed for the case of High Harmonic Fast wave (HHFW) heating in NSTX. The RF field data needed for the RF kick operator is obtained from TORIC runs. The MCGO runs are made in both zero-orbit-width and finite-orbit-width configurations. Of particular interest are the fast ion loss spectra to the 2D wall. A procedure for accumulation of particle loss distributions to the wall of test ions and neutrals is included as a function of poloidal and toroidal distance along the wall, particle energy, and the incident angle. With the applied RF power, the count of lost ions is increased only moderately, however, the heat load to the wall is increased by 60%. [ABSTRACT FROM AUTHOR]

In this work we present an overview of ion cyclotron emission (ICE) signals observed on ASDEX Upgrade (AUG) with a B-dot probe array [1]. The array was recently augmented with an 8 channel digitizer (up to 250 MHz sampling rate) that makes it possible to measure a phase from up to 8 (out of 12) probes. This diagnostic upgrade allows to measure the field-aligned (∼toroidal) propagation direction and the mode number for ICE. The high-frequency Alfvén eigenmode is a commonly observed instability in NBI-heated plasmas on AUG. The frequency of this mode is typically around half the on-axis cyclotron frequency of the driving fast ion species. The mode characteristics measured with the improved ICE diagnostic are consistent with the shear-polarized (or global) Alfvén eigenmode: the mode propagates toroidally in the counter-current, counter-injection direction with a high (>20) mode number. Core ICE is also commonly observed in NBI-heated discharges on AUG. These signal spectra match the on-axis cyclotron frequency (and higher harmonics) of the driving fast ion species and the excitation mechanism is consistent with the magnetoacoustic cyclotron instability (MCI). The recent toroidal phase measurements show that we are dealing with a nearly perpendicularly (to the background magnetic field) propagating wave, in line with the MCI picture. [ABSTRACT FROM AUTHOR]

This work studies the impact of the Ion Cyclotron Resonance Heating (ICRH) of the fast Neutral Beam Injected (NBI) D and T ions on the fusion performance in recent JET DTE2 campaign. The effect of the Radio Frequency (RF) wave on fast NBI D and T ion dynamics was analyzed by means of TRANSP simulations. Moderate increase, 5-10%, in DT reaction rates was predicted by TRANSP for the case of ICRH heating of fast NBI D ions at n=2 harmonic of ion cyclotron resonance. The simulations have shown that synergistic interaction between fast NBI T ions and RF waves have little or no impact on the fusion performance in the experimental conditions discussed here. Contribution of various heating and fast ion sources have been assessed and discussed. The absence of strong interaction between fast NBI T ions and RF waves was attributed to the poorer penetration of the T beams leading to lower fast T ion densities in the core and the lower perpendicular velocity of the fast NBI T ions resulting in diminished intensity of fast particle – RF wave interaction. [ABSTRACT FROM AUTHOR]

Experiments in various tokamaks and their analysis identify the fast ions (FI) generated by NBI and/or ICRF heating as one of the main causes of the observed improvement in core confinement: fast ions can reduce core microturbulence (mainly Ion-Temperature-Gradient (ITG) driven modes) either electrostatically or electromagnetically, or they can resonate with fishbones and high-frequency Alfvén modes, which in turn contribute in stabilizing ITG. In this perspective, we discuss recent experiments done on ASDEX Upgrade (AUG) where ICRF is the main actuator for FI generation for energies above 100 keV. Additionally, ICRF-FIs can substantially impact the MHD activity and its consequent effects on fast ion losses (FILs) and ion-cyclotron emission (ICE). We present dedicated AUG experiments with NBI-D further accelerated by ICRF. [ABSTRACT FROM AUTHOR]

Beam-target reactions are responsible for a substantial fraction of the fusion power generated in D-T plasmas in JET-ILW (Be/W-wall), with ion temperatures of 10-12keV and large neutral-beam injection (NBI) power. It is known that injecting D beam ions with energies of ∼100-150keV in T-rich plasmas has a larger potential for beam-target fusion than in 50:50 D:T plasmas, but such a scenario was never developed in the past D-T experiments performed in JET-C (Carbon-wall) and in TFTR in the 90's. On top of the intrinsic advantages of using D beams in T-rich plasmas for D-T neutron production, simulations have shown that fundamental ion-cyclotron resonance heating (ICRH) of the D ions can significantly boost the net fusion reactivity, since both the thermalized D ions and the fast D-NBI ions are accelerated to energy ranges that are optimal for the D-T reaction cross-section. The beneficial effect of fundamental D ICRH on thermal D minorities in tritium plasmas (without NBI) was identified in the JET-C D-T experiments, but was not tested in high performance H-mode discharges with D-NBI heating. In 2021, dedicated JET-ILW DTE2 [1] experiments confirmed - for the first time - the improved fusion performance of T-rich plasmas with high D-NBI power and highlighted the key impact of fundamental D ICRH on the fusion reactivity. This new scenario lead to the world-wide 5s averaged fusion power (and energy) record in D-T tokamak plasmas with dominant beam-target reactions. A brief experimental overview followed by detailed RF wave / Fokker-Planck simulations including NBI-ICRH synergy will be presented, to disentangle the different components contributing to the high neutron yield achieved in these experiments. [ABSTRACT FROM AUTHOR]

Experimental studies of Deuterium and Tritium plasmas have been carried out at JET in the last years, yielding precious information for the next generation of fusion devices. Among the various approaches taken, JET's "Baseline" scenario experiments are pushing the machine towards its engineering limits by operating in a high-confinement H-mode at high toroidal field, plasma current and fuel density, as planned for ITER. The present paper provides a brief sketch of the Baseline scenario philosophy and discusses a number of RF-related results obtained in the preparation of the DT campaign as well as its preparations. Fusion powers of almost 9MW and energies of 12MJ have been reached in DT "Baseline" scenario plasmas. The differing role of radio frequency and beam heating is highlighted, the former allowing peaked core temperature profiles instrumental e.g. for core high-Z impurity chasing and the "landing" of high performance discharges while the latter is the main overall heating source in JET. Synergistic effects from the simultaneous use of wave and beam heating are responsible for a modest but noticeable increase in fusion power. One of the differences between D and DT plasmas is the plasma density, which impacts on the beam deposition as well as fast ion generation. [ABSTRACT FROM AUTHOR]

The viability of magnetic confinement fusion as an energy source depends on achieving the high ion temperatures required for D-T fusion. Among the available techniques, plasma heating with waves in the ion cyclotron range of frequencies (ICRF) is a prominent method for bulk ion heating in fusion plasmas. Furthermore, a detailed understanding of the non-linear physics of alpha heating and the complex impact of MeV-range fast ions on plasma dynamics becomes progressively more important. This paper provides a comprehensive overview of recent developments with the three-ion ICRF scenarios on Alcator C-Mod, ASDEX Upgrade and JET tokamaks. The results demonstrate the flexibility of these novel scenarios for heating bulk ions in D-T ≈ 50%-50% plasmas and efficient generation of MeV-range fast ions in multi-ion species plasmas. Several key results relevant for ITER and future fusion reactors are highlighted. [ABSTRACT FROM AUTHOR]

Metal hydrides have attracted much interest from the viewpoint of hydrogen storage material. In general, it is known that hydride ion exhibits faster ion conducting property, in comparison with proton. Further, when hydrogen exists as negatively charged hydride ion within solid, it works as labile part. In this study, perovskite-type lithium hydride BaLiH3 has been focused on, from the viewpoint of Li-H-Li bonding change. Molecular orbital calculations using hybrid density functional theory were performed for both BaLi8H12 and LiLi8H12 models. From chemical bonding rule, it was found that covalent Li-H-Li bonding is formed. When lithium defect is doped at the cubic centre, it was discovered that lithium cation is fluctuated within Li8H12 cube, combined with the change of Li-H-Li bonding strength. [ABSTRACT FROM AUTHOR]

BTR code, which is generally used for neutral beamline design and optimization, is applied to calculate the injected beam stopping in plasma, beam ionization and current drive in a fusion neutron source DEMO-FNS. The beam- plasma model implements detailed spatial and angular distributions of the injected beam taking into account the multi- channel injector geometry and operating parameters. The beam ionization incorporates the stopping cross-section fits by Janev-Suzuki. The beam's instant 3D deposition in a plasma is compared for various beam geometries. The beam losses and detailed shine-through images are obtained taking into account beam aberrations in the 3D plasma target. The fast ion current profiles are evaluated with a simple slowing-down procedure. The influence of beam size, beamlet focusing and inner divergence is proved to be essential for beam deposition and current drive efficiency. The aberrations of tangential beam decay in toroidal plasmas lead to beam profile asymmetry, which can be potentially critical for the current drive - especially when thick and divergent beams are injected off-axis. [ABSTRACT FROM AUTHOR]

Inert surrogates for high explosives provide low-risk options to study their basic material response to extreme conditions such as high pressure and high strain rates. Meso-Erythritol is under evaluation as a shock surrogate for Pentaerythritol Tetranitrate (PETN) due to their similar density, crystal structures, and melting points. However, no Hugoniot data for Meso-Erythritol currently exists. Preliminary gas gun experiments were performed to test a setup for determining the Hugoniot of Meso-Erythritol as a powder compact at 1.18 g/cc (82% theoretical maximum density). Photon doppler velocimetry was used to measure particle velocities. Experiments investigated impact velocities of up to 450 meters per second, and the testing conditions were used to inform hydrocode simulations. Initial results suggest that the resulting particle velocity in Meso-Erythritol is lower than PETN when compared to hydrocode simulations and that shock decay in Meso-Erythritol is faster than PETN. [ABSTRACT FROM AUTHOR]

An important test for W7-X is to demonstrate confinement of fast trapped ions at volume averaged beta values up to 5%, corresponding to plasma densities above 1020 m−3. Energetic ions in W7-X with energies 50 < E < 100 keV mimic alphas in a reactor. To generate such a population is a challenging task in high-density plasmas but this can be efficiently realized with the H- (3He)-D three-ion heating ICRH scenario, foreseen for f∼25 MHz in W7-X. An ICRH system is prepared for W7-X, expected to deposit RF powers up to ∼1.5 MW (depending on the coupling) at frequencies between 25-38 MHz in pulses up to 10s. A two-strap ICRH antenna for W7-X is under construction. Each strap of the antenna is on one side connected to a tuning capacitor and grounded to the antenna box at the other end. A prematching has been implemented by connecting the RF transmission lines at an intermediate position on each strap. The main dimensions of straps and antenna box have been optimized to maximise the power delivered to the plasma, using the reference plasma density profile in front of the antenna, provided by the W7-X team. A dedicated test stand is under construction to check the main functional tests of the full ICRH antenna system. [ABSTRACT FROM AUTHOR]

The influence of ELMs on the propagation of fast wave in the ion cyclotron range of frequency is studied. The 3D edge turbulence code BOUT++ with the Six-field two-fluid model is used to calculate the perturbed density during ELMs, and the antenna code RAPLICASOL is then applied to calculate the antenna fields using the calculated 3D density. The results indicate that ELMs can cause an electric field perturbation in the range of 4.5% - 45% for an ELM induced density perturbation in the range of 3%-30%. [ABSTRACT FROM AUTHOR]

A tritium (T) campaign is planned in preparation for the deuterium-tritium (D-T) campaign at the Joint European Torus (JET). These experiments will be the first experiments involving T with the ITER-like plasma-wall facing components materials. They will give a unique opportunity to test one of the most promising ion cyclotron resonance frequency (ICRF) heating schemes for ITER plasmas: the 2nd tritium (T) harmonic resonance (ω = 2ωT). This paper provides two key contributions related to modelling of the performance of this scheme at JET. First, we assess the heating performance of the 2nd T harmonic resonance and, second, we model different ICRF schemes for the T campaign in support for the D-T campaign, i.e., identify differences and similarities from the heating point of view between T and D-T plasmas in order to predict the performance of ω = 2ωT in the D-T scenario. In our modelling we use a selected hybrid record discharge as reference, i.e., using its experimental profiles. We consider two ICRF schemes (6 MW), i.e. ω = ω3He = 2ωT (no 3He), with a central resonance and three NBI power outputs (15, 25 and 35 MW) in two plasma compositions (100% T and 50%:50% D-T). Note that isotope effects are not taken into account in these simulations. For this study, the ICRF and NBI heating are modelled with the ICRF code PION and the beam code PENCIL which take into account the ICRF+NBI synergy. The analysis of the T velocity distribution function shows that a stronger tail is formed in those plasmas with lower tritium density. This fact has an important impact on the slowing-down process of fast tritons with the background species. The T plasma shows a higher and more peaked ion-ion collisional power density at the plasma centre as compared to D-T plasma. In the T plasma, ICRF heating drives fast tritons at the plasma centre with an average energy substantially lower than in the other case. On the other hand, the use of 3He as a minority makes the fast ion T energy considerably lower due to strong 3He absorption. Fast ion average energies reached at the plasma centre are similar in all species mixture cases. As a result, there is a strong heating similarity between T and D-T. However, it is crucial to study the generation of a strong T tail as a result of particle-wave interaction which is not possible under this scheme and needs to be studied in plasmas without 3He in preparation of JET D-T campaign and ITER. Therefore, both schemes (ω = ω3He = 2ωT and ω=2ωT) need to be tested. [ABSTRACT FROM AUTHOR]

In 2018, Ion Cyclotron Resonant Frequency (ICRF) waves were for the first time applied to the WEST plasma scenarios. In ICRF-only plasmas at medium density, or on top of a low level of Lower Hybrid (LH) power, the coupled ICRF power increases the plasma energy content. However in discharges with large LH power at high core density, nearly all the applied ICRF power gets radiated, mainly in the plasma bulk. Both the energy content and conducted power decrease. Two peculiarities of WEST, that may combine, are presently invoked to explain this phenomenology:1) Fast ion ripple losses, evidenced between TF coils on the baffle, likely degrade the ICRF heating efficiency. 2) RF-enhanced W sources, evidenced on several Plasma-Facing Components (PFCs), likely over-contaminate the high-power plasmas. [ABSTRACT FROM AUTHOR]

This paper reports the significant advancement of our ability to model and to understand how RF waves interact with the SOL plasma, by simulating the full torus 3D SOL plasma together with the antenna and core plasma. We introduce and use a recently developed and open source code, Petra-M, which was constructed on the scalable MFEM C++ finite element library, and performed 3D full wave simulations in the HHFW regime for both NSTX-U and LAPD plasmas. A first full wave simulation for a full 3D torus including a realistic antenna geometry and SOL plasma region for NSTX-U is presented. A scan of the antenna phasing shows a strong interaction between FWs and the SOL plasma for lower antenna phasing, which is consistent with previous NSTX HHFW observations. The effect of the 3D wave field on the fast ion population from NBI beams in NSTX-U is also discussed by using the 3D field obtained from the Petra-M simulations in the full-orbit following particle SPIRAL code. On LAPD, 3D full wave simulations of a new HHFW 4-strap antenna recently installed by TAE Technologies on LAPD are performed showing a qualitative agreement with experimental data. [ABSTRACT FROM AUTHOR]

This study compares experimental observations on the two challenges of Ion Cyclotron Resonance Heating (ICRH), namely the coupling of waves to the plasma and the enhanced impurity sputtering in EAST and WEST medium size tokamaks. In WEST, Lower Hybrid (LH) power helps improving ICRH coupling. In both machines experiments reveal that fueling from the midplane not only helps to couple waves from nearby antennas like in other devices, but also has an impact on the scrape-off layer (SOL) density in regions that are not magnetically connected to the valves. Localized midplane nozzle valves allow similar (in WEST) or better (in EAST) coupling compared to poloidally distributed valves. Core density control requirements for long-pulse operation, in particular in L-mode regime, however limit the amount of gas that can be injected. During ICRH impurities can contaminate the plasma up to a level detrimental for the operation, e.g. up to 100% of ICRH power can be radiated on WEST in certain high power conditions. In WEST, tungsten (W) production measured by visible spectroscopy increases on all the observed objects during ICRH compared to a reference phase without ICRH. On some components (antenna side limiters, baffle, divertor) the rise is larger than with a similar LH power. The relative contribution of each object and physical process (RF-sheaths, fast ion ripple losses) to core contamination yet remains poorly known. Comparing antenna limiters with W-coating vs low-Z materials would help quantifying the role of these components. In EAST, the core W content, measured by EUV spectroscopy in presence of divertor sources only, is correlated with the total injected power, either from ICRH or LH. Since 2018 the LH guard limiter tiles were W-coated. Their contribution to the core W content appears more important than divertor sources when two-strap ICRH antennas magnetically connected to W components at the midplane is powered, compromising high performance operations. [ABSTRACT FROM AUTHOR]

The studies of recent JET experiments in H/D≈0.85/0.15 plasma (2.9T/2MA) in which neutron rate was enhanced by applying 2.5MW of ICRH using D-(DNBI)-H three-ion scheme are reported. An extensive analysis of this novel heating scenario has been carried out by means of integrated TRANSP/TORIC modelling, and a comprehensive validation of the computed Fast Ion Distribution Function (FI DF) with a range of fast ion diagnostics available at JET is presented. The predicted acceleration of D Neutral Beam Injection (NBI) ions beyond their injection energies and the associated changes in FI DF by RF waves are found to be in good agreement with measured neutron yield and TOFOR neutron spectrometer measurements, as well as with multi-channel neutron camera observations and neutral particle analyser diagnostic. An outlook of the possible applications of the developed technique for future DTE2 studies on JET has been highlighted. Controlled acceleration of TNBI ions in D-rich and DNBI ions in T-rich plasmas to optimal energies can be applied to maximise BT fusion rates and contribute to the success of future DT experiments at JET and ITER as illustrated in this study. [ABSTRACT FROM AUTHOR]

Radio frequency (RF) power in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating techniques for Experimental Advanced Superconducting Tokamak (EAST). In this paper, we will present an overview of the main experimental results from recent campaign on EAST. 1) A dedicated experiment for more than 10MW operations has been carried out on EAST. The major aspects linked to the use of the EAST auxiliary heating systems: ICRF,LHCD and NBI are presented with emphasis on ICRF and LH. The challenges for ICRF coupling on EAST will be described at the low densities typically used for long pulse operation with lithium wall conditioning. 2)This paper also summarizes effects of ICRF power on LH coupling and modification of heat loads on EAST. 3) Co-current rotation driven by ICRF are observed in both L-mode and H-mode discharges. Co-current rotation can be generated by ICRF heating in LHCD plasma. Different rotation behavior observed in LHCD discharges. ICRF can also induce counter-current rotation in LHCD L-mode discharges. 4) A high-frequency magnetic probes (HFBs) system has been developed and successfully applied to detect ion cyclotron emission (ICE) in D-NBI injection experiments in the 2018 experimental campaign of EAST. ICE driven by fast D-NBI ions and fusion born ions are observed on EAST.5) In Hydrogen minority in Deuterium plasma, the interaction of fast wave and fast D-NBI ions is detected on EAST. Acceleration of fast D ions is confirmed by increased neutron yield. [ABSTRACT FROM AUTHOR]

In this work, collision processes between C6+, O8+ and Si13+ ions and H2O molecules that lead to target ionization are studied by means of the classical trajectory Monte Carlo method. We employ an 8-electron model in which the H2O electron densities and energies dynamically adapt during ionization processes to those corresponding to the H2Oq+ ions by assuming vertical transitions between the different molecular ionic states. Net total ionization cross sections and single differential cross sections in energy and angle are shown for 4 MeV/u projectiles and compared to available experimental data and theoretical predictions from distorted wave models. [ABSTRACT FROM AUTHOR]

Argonne National Laboratory (ANL) and the Department of Radiation and Cellular Oncology at the University of Chicago (UChicago) are investigating the feasibility of developing an innovative heavy ion therapy center by combining an advanced compact heavy ion linac (ACCIL) designed at Argonne with real-time image-guided therapy. The proposed technology will not only be the first linac-based heavy-ion therapy technology in the world, with the advantage of much desired fast energy and ion switching capability, but also the first real-time image-guided heavy ion therapy modality. ANL has a prime location to house such a development within existing infrastructure and radiation enclosure at the former Intense Pulsed Neutron Source (IPNS) site. The cost of developing the technology and building a linac-based ion therapy facility on the existing ANL site will be significantly lower than the “green field” carbon ion therapy centers proposed elsewhere. Such a facility would prove a unique platform to stage the development of pre-clinical studies to prepare for Federal Drug Administration (FDA) clearance for carbon and other ion beam therapies in the US, and pave the way to establishing a clinical therapy facility in the Chicago area. In addition to discovery science in high-gradient accelerator physics and the development of superconducting heavy-ion gantry for therapy delivery coupled with real-time guidance, the proposed facility will enable a breadth of research and applications, and as such, will serve as the advanced particle therapy research center in the US. Potential research topics include cellular radiobiology comparative studies of different ion beam therapies and the development of real-time imaging for precise and accurate dose delivery. The ANL/UChicago Advanced Heavy Ion Therapy Center initiative has recently grown to include the regional and nationwide interest, support and collaboration of Northwestern University, the Chicago Proton Center, the Hines Illinois branch of the Department of Veteran Affairs (VA), as well as the National Center for Particle Beam Radiation Therapy Research. [ABSTRACT FROM AUTHOR]

Super ionic conductors (e.g.; A3M2(XO4)3, A=Li, Na) have received attention in applied research due to their interesting electrochemical property and inherently high ionic conductivity [1]. However, structural and compatibility requirements for fast ion transport is stringent and it plays a crucial role. In A3M2(XO4)3, a suitable cage formation in the crystal framework due to corner sharing arrangement of XO4 tetrahedra and MO6 octahedra creates voids that acts as host/guest site for cation transport. In this work, we report Nasicon structure Na3Fe2(PO4)3 (NFP) prepared via sol-gel route mediated by citric acid. Structural analysis confirmed that NFP sample belongs to monoclinic crystal structure having Cc space group (S. G. No 9) with lattice parameters, a=15.106 Å, b=8.722 Å, c=8.775 Å and β=124.96°. Electrical properties of the prepared sample have been studied by AC impedance spectroscopy technique. The AC conductivity results indicated typical signature of ionically conducting system. [ABSTRACT FROM AUTHOR]

Three diagnostic systems are being developed in Ioffe Institute for ITER. Those are Neutral Particle Analysis (NPA), Thomson Scattering in Divertor (TSD) and Gamma Spectroscopy (GS). The main objective of NPA in ITER is to measure D/T fuel ration in plasma on the basis of measurement of neutralized fluxes of D and T ions [1]. Fuel ratio is one of the key parameters needed by ITER control system to provide the optimal conditions in plasma and the most effective plasma burning. Another objective is to measure the distribution function of fast ions (including alpha particles) generated as a result of the additional heating and nuclear fusion reactions. Thomson Scattering in Divertor (TSD) [2] will be used to measure electron temperature and density in the scrape-off layer in outer leg of ITER divertor. The main task of TSD is to protect the machine from divertor overloading. Gamma Spectroscopy (GS) [3] is based on the measurement of spectral lines of MeV range gammas generated in nuclear reactions in plasma. 2-D gamma-ray emission measurements give valuable information on the confined alpha particles in DT plasma. They also provide important information on the location of MeV range runaway electron beams in ITER plasma. For all three cases the physical basis and instrumentation are presented. The simple NPA version for measurements of D/T ratio in DEMO is also briefly described. [ABSTRACT FROM AUTHOR]

Gamma diagnostics is considered to be primary for the confined a- particles and runaway electrons measurements on ITER. The gamma spectrometer will be embedded into a neutron dump of the ITER Neutral Particle Analyzer diagnostic complex. It will supplement NPA measurements on the fuel isotope ratio and confined alphas/fast ions. In this paper an update on ITER gamma spectrometer developments is given. A new geometry of the system is described and detailed analysis of expected signals for the spectrometer is presented. [ABSTRACT FROM AUTHOR]

The Mega Ampere Spherical Tokamak Upgrade (MAST Upgrade) is intended as a demonstration of the physics viability of the Spherical Tokamak (ST) concept and as a platform for contributing to ITER/DEMO physics. Concerning physics exploitation, MAST Upgrade plasma scenarios can contribute to the ITER Tokamak physics particularly in the field of fast particle behavior and current drive studies. At present, MAST is equipped with a prototype neutron camera (NC). On the basis of the experience and results from previous experimental campaigns using the NC, the conceptual design of a neutron camera upgrade (NC Upgrade) is being developed. As part of the MAST Upgrade, the NC Upgrade is considered a high priority diagnostic since it would allow studies in the field of fast ions and current drive with good temporal and spatial resolution. In this paper, we explore an optional design with the camera array viewing the poloidal section of the plasma from different directions. [ABSTRACT FROM AUTHOR]

Understanding the behaviour of the confined fast ions is important in both current and future fusion experiments. These ions play a key role in heating the plasma and will be crucial for achieving conditions for burning plasma in next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS) is well suited for reactor conditions and offers such an opportunity by providing measurements of the confined fast-ion distribution function resolved in space, time and 1D velocity space. We currently operate a CTS system at ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A new setup using two independent receiver systems has enabled improved subtraction of the background signal, and hence the first accurate characterization of fast-ion properties. Here we review this new dual-receiver CTS setup and present results on fast-ion measurements based on the improved background characterization. These results have been obtained both with and without NBI heating, and with the measurement volume located close to the centre of the plasma. The measurements agree quantitatively with predictions of numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade are now feasible. The new background subtraction technique could be important for the design of CTS systems in other fusion experiments. [ABSTRACT FROM AUTHOR]

The ion cyclotron emission (ICE) is triggered by the free energy from an anisotropic distribution of fast ions in cyclotron resonance with plasma waves. Several theories have been developed in the hope of using the spectrum featured by this emission to extract information on the fast ion population [3], but the strong coupling between the fast ions orbits, their energy profile and the plasma waves properties makes it difficult to disentangle the role of each actor in the emission. We present here the three main results which, once combined, have improved our understanding of ICE on ASDEX Upgrade: (1) the measurement of all the main types of ICE which enables a comparison of their properties and of their interactions, (2) the use of a fast acquisition system with an increased accuracy in the time and frequency processing of the signal where the fine structure of the emission is resolved and (3) the use of the Hamiltonian theoretical framework developed for ICRF heating. It unifies the analysis of large extension orbits and of their interactions with the plasma waves and reveals the respective roles of the fast ions (through their velocities) and of the waves (through their frequencies and wave numbers) in the resonance condition. If these results are confirmed on other machines, they could lead to the development of a non intrusive diagnostic for fast ions. [ABSTRACT FROM AUTHOR]

Radiation hydrodynamics 1D simulations were performed with two concurrent codes, DEIRA and RAMPHY. The DEIRA code was used for DT capsule implosion and burn, and the RAMPHY code was used for computation of X-ray and fast ions deposition in the first wall liquid film of the reactor chamber. The simulations were run for 740 MJ direct drive DT capsule and Pb thin liquid wall reactor chamber of 10 m diameter. Temporal profiles for DT capsule leaking power of X-rays, neutrons and fast 4He ions were obtained and spatial profiles of the liquid film flow parameter were computed and analyzed. [ABSTRACT FROM AUTHOR]

Analysis of fast-ion distributions >100 Te is important for both ITER and a fusion reactor, as both will have a significant population of fusion-born alpha particles. Furthermore, energetic ions may display transport properties that differ from the bulk plasma. It is imperative to benchmark current simulation codes with measurements of highly energetic fast-ions on current devices. Experimental measurements of ICRF heated H-minority plasmas on Alcator C-Mod are performed with an upgraded Compact Neutral Particle Analyzer (CNPA). The CNPA consists of vertically-viewing photodiode detectors with viewing chords from r/a = ∼0.18 to 0.6 and energies from 150 keV to 1.5 MeV. The CNPA measurements are compared to the output of a synthetic diagnostic that has been added to the Fokker-Planck solver CQL3D. CQL3D is coupled with the full-wave solver AORSA to evolve a self-consistent fast-ion distribution. Good agreement is obtained between simulation and experiment for fast ion distributions that are in steady-state (df/dt = 0). However, there are discrepancies between the experimental and simulated results for the time-dependent evolution of the fast-ion distribution. A possible explanation of the discrepancy is due to violation of certain assumptions of quasi-linear theory. [ABSTRACT FROM AUTHOR]

ICRF is the primary auxiliary heating in C-Mod where both H or 3He minority and mode conversion regimes are utilized. For transport analysis, the power deposition profile is critical and measuring the resulting fast ion distribution provides a direct means to constrain and validate ICRF simulations used to calculate power deposition. In mode conversion, measurement of the minority ion density, temperature, and velocity profiles is critical for the wave physics and may provide some insight into the fundamental physics of flow drive. Using active charge exchange, the He+1 4686Å or H 6563Å line is observed to find whether fast ion and relevant thermal ion measurements are practical. Results of these experiments yield fast ion and thermal ion measurements in D(He). A new analysis technique to extract information from high noise fast ion spectra is developed. A development path for improved D(3He) and D(H) is indicated. [ABSTRACT FROM AUTHOR]

Alcator C-Mod uses ICRF for the bulk auxiliary heating and relies primarily on hydrogen minority heating scenarios. Measuring the resulting hydrogen ion distribution provides an opportunity to validate upgraded ICRF simulation capability that includes non-Maxwellian ions. The Compact Neutral Particle Analyzer (CNPA) is a diagnostic employed on Alcator C-Mod to measure this fast ion distribution function. The diagnostic can measure the energy distribution of the fast ion tail, serving as a benchmark for simulation results and allowing for an assessment of the simulation algorithm and physics kernel. In this poster, we will present results from the detector in the most recent campaigns. We will discuss the calculation of the fast ion distribution from the measured CNPA distribution and the resulting effective temperature from applying a Stix fit to this distribution. [ABSTRACT FROM AUTHOR]

A study of magnetically confined fast ions in tokamaks plays an important role in burning plasma research. To reach ignition and steady burning of a reactor plasma an adequate confinement of energetic ions produced by NBI heating, accelerated with ICRF and born in fusion reactions is essential to provide efficient heating of the bulk plasma. Thus, investigation of the fast ion behaviour is an immediate task for present-day large machines, such as JET, in order to understand the main mechanisms of slowing down, redistribution and losses, and to develop optimal plasma scenarios. Today's JET has an enhanced suite of fast ion diagnostics both of confined and lost ions that enable to significantly contribute to this important area of research. Fast ion populations of p, d, t, 3He and 4He, made with ICRF, NBI, and fusion reactions have been investigated in experiments on JET with sophisticated diagnostics in conventional and shear-reversed plasmas, exploring a wide range of effects. This paper will introduce to the JET fast-ion diagnostic techniques and will give an overview of recent observations. A synergy of the unique diagnostic set was utilised in JET, and studies of the response of fast ions to MHD modes (e.g. tornado modes, sawtooth crashes), fast 3He-ions behaviour in shear-reversed plasmas are impressive examples of that. Some results on fast ion losses in JET experiments with various levels of the toroidal field ripple will be demonstrated. [ABSTRACT FROM AUTHOR]

We summarize the TJ-II stellarator device give an outline of a vacuum ultraviolet spectrometer used for performing spectral surveys specialized plasma studies. Next, we report the main impurities observed in hot plasmas created maintained by electron cyclotron resonance neutral beam injection heating with lithium coated wall conditioning. Finally, we report broad emission structures that have been observed close to strong oxygen emission lines during neutral beam injection heating phases we elucidate their possible origin. [ABSTRACT FROM AUTHOR]

Recently, hydride ion has attracted much scientific interest, from the viewpoint of fast ion-conduction. It was reported that La2LiHO3 perovskite, which has K2NiF4−type structure, exhibits hydride ion-conductivity. In this study, hydride ion-conducting mechanism on two-dimensional LiOH layer has been investigated, using hybrid density functional theory (OFT) calculations. When hydrogen is allocated at two-dimensional, structural deformation appears, due to O-H-O covalent bonding formation. On the other hand, hydrogen is destabilised at lattice position because of the lability of negatively charged hydrogen. [ABSTRACT FROM AUTHOR]