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Proceedings of the 24TH TOPICAL CONFERENCE ON RADIO-FREQUENCY POWER IN PLASMAS 26–28 September 2022 Annapolis, USA, 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., This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 – EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them. We thank the ITPA Energetic Particle Physics Topical Group for its support. Part of this work was also carried out in the framework of projects done for the ITER Scientist Fellow Network (ISFN). ITER is the Nuclear Facility INB No. 174. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. This publication is provided for scientific purposes only. Its contents should not be considered as commitments from the ITER Organization as a nuclear operator in the frame of the licensing process., Peer Reviewed, "Article signat per 78 autors/es: Ye. O. Kazakov; J. Ongena; M. Nocente; V. Bobkov; J. Garcia; V. G. Kiptily; M. Schneider; S. Wukitch; J. C. Wright; M. Dreval; K. K. Kirov; S. Mazzi; R. Ochoukov; S. E. Sharapov; Ž. Štancar; H. Weisen; Y. Baranov; M. Baruzzo; A. Bierwage; R. Bilato; A. Chomiczewska; R. Coelho; T. Craciunescu; K. Crombé; E. Delabie; E. de la Luna; R. Dumont; P. Dumortier; F. Durodié; J. Eriksson; M. Fitzgerald; J. Galdon-Quiroga; D. Gallart; M. Garcia-Munoz; L. Giacomelli; C. Giroud; J. Gonzalez-Martin; A. Hakola; R. Henriques; P. Jacquet; I. Jepu; T. Johnson; A. Kappatou; D. Keeling; D. King; C. Klepper; Ph. Lauber; M. Lennholm; E. Lerche; B. Lomanowski; C. Lowry; M. J. Mantsinen; M. Maslov; S. Menmuir; I. Monakhov; F. Nabais; M. F. F. Nave; C. Noble; E. Panontin; S. D. Pinches; A. R. Polevoi; D. Rigamonti; A. Sahlberg; M. Salewski; P. A. Schneider; H. Sheikh; K. Shinohara; P. Siren; S. Sumida; A. Thorman; R. A. Tinguely; D. Valcarcel; D. Van Eester; M. Van Schoor; J. Varje; M. Weiland; N. Wendler; JET Contributors, the ASDEX Upgrade Team and the EUROfusion MST1 Team", Postprint (author's final draft)

We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be distinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions.

Fast ions in the MeV-range can be diagnosed by neutron emission spectroscopy (NES) and gamma-ray spectroscopy (GRS). In this work, we present orbit weight functions for one-step fusion reactions, using NES and GRS diagnostics on perpendicular and oblique lines-of-sight (LOS) at Joint European Torus (JET) as examples. The orbit weight functions allow us to express the sensitivities of the diagnostics in terms of fast-ion (FI) orbits and can be used to swiftly reproduce synthetic signals that have been computed by established codes. For diagnostically relevant neutron energies for the D(D, n)He-3 reaction, the orbit sensitivities of the NES diagnostics follow a predictable pattern. As the neutron energy of interest increases, the pattern shifts upwards in FI energy. For the GRS diagnostic and the T(p,gamma)He-4 reaction, the orbit sensitivity is shown to be qualitatively different for red-shifted, blue-shifted and nominal gamma birth energies. Finally, we demonstrate how orbit weight functions can be used to decompose diagnostic signals into the contributions from different orbit types. For a TRANSP simulation of the JET discharge (a three-ion ICRF scenario) considered in this work, the NES signals for both the perpendicular and oblique LOS are shown to originate mostly from co-passing orbits. In addition, a significant fraction of the NES signal for the oblique LOS is shown to originate from stagnation orbits.

Alfven eigenmode (AE) instabilities driven by alpha-particles have been observed in D-He-3 fusion experiments on the Joint European Torus (JET) with the ITER-like wall. For the efficient generation of fusion alpha-particles from D-He-3 fusion reaction, the three-ion radio frequency scenario was used to accelerate the neutral beam injection 100 keV deuterons to higher energies in the core of mixed D-He-3 plasmas at high concentrations of He-3. A large variety of fast-ion driven magnetohydrodynamic modes were observed, including the elliptical Alfven eigenmodes (EAEs) with mode numbers n = -1 and axisymmetric modes with n = 0 in the frequency range of EAEs. The simultaneous observation of these modes indicates the presence of rather strong alpha-particle population in the plasma with a 'bump-on-tail' shaped velocity distribution. Linear stability analysis and Fokker-Planck calculations support the observations. Experimental evidence of the AEs excitation by fusion-born alpha-particles in the D-He-3 plasma is provided by neutron and gamma-ray diagnostics as well as fast-ion loss measurements. We discuss an experimental proposal for the planned full-scale D-T plasma experiments on JET based on the physics insights gained from these experiments.

This paper briefly describes intrinsic and collaborative scientific activities in the Stellarator Department of the Institute of Plasma Physics of the National Science Center "Kharkov Institute of Physics and Technology" in last two years. These activities include experiments on JET tokamak, stellarators Wendelstein 7-X and Uragan-2M, TOMAS toroidal device and theoretical studies related to modeling of radio-frequency fields in plasma and conceptual development of the stellarator-mirror fission-fusion hybrid.

Various types of Alfvén eigenmodes (AEs) have been destabilized by fast ions over a broad frequency range from ∼80 kHz to ∼700 kHz in a series of JET experiments in mixed D–3He plasmas heated with the three-ion ICRF scenario (2020 Nocente et al Nucl. Fusion 60 124006). In this paper, we identify the radial localization of AEs using an X-mode reflectometer, a multiline interferometer and soft x-ray diagnostics. The analysis is focused on the most representative example of these measurements in JET pulse #95691, where two different types of Alfvén cascade (AC) eigenmodes were observed. These modes originate from the presence of a local minimum of the safety factor q min. In addition to ACs with frequencies below the frequency of toroidal Alfvén eigenmodes (TAEs), ACs with frequencies above the TAE frequency were destabilized by energetic ions. Both low- (f ≈ 80–180 kHz) and high-frequency (f ≈ 330–450 kHz) ACs were localized in the central regions of the plasma. The characteristics of the high-frequency ACs are investigated in detail numerically using HELENA, CSCAS and MISHKA codes. The resonant conditions for the mode excitation are found to be determined by passing ions of rather high energy of several hundred keV and similar to those established in JT-60U with negative-ion-based NBI (2005 Takechi et al Phys. Plasmas 12 082509). The computed radial mode structure is found to be consistent with the experimental measurements. In contrast to low-frequency ACs observed most often, the frequency of the high-frequency ACs decreases with time as the value of qmin decreases. This feature is in a qualitative agreement with the analytical model of the high-frequency ACs in Breizman et al (2003 Phys. Plasmas 10 3649). The high-frequency AC could be highly relevant for future ITER and fusion reactor plasmas dominated by ∼MeV energetic ions, including a significant population of passing fast ions.

Long-pulse operation of a self-sustained fusion reactor using toroidal magnetic containment requires control over the content of alpha particles produced by D-T fusion reactions. On the one hand, MeV-class alpha particles must stay confined to heat the plasma. On the other hand, decelerated helium ash must be expelled before diluting the fusion fuel. Here, we report results of kinetic-magnetohydrodynamic hybrid simulations of a large tokamak plasma that confirm the existence of a parameter window where such energy-selective confinement can be accomplished by exploiting internal relaxation events known as sawtooth crashes. The physical picture — a synergy between magnetic geometry, optimal crash duration and rapid particle motion — is completed by clarifying the role of magnetic drifts. Besides causing asymmetry between co- and counter-going particle populations, magnetic drifts determine the size of the confinement window by dictating where and how much reconnection occurs in particle orbit topology.

Alfvén eigenmode (AE) instabilities driven by alpha-particles have been observed in D-3He fusion experiments on the Joint European Torus (JET) with the ITER-like wall. For the efficient generation of fusion alpha-particles from D-3He fusion reaction, the three-ion radio frequency scenario was used to accelerate the neutral beam injection 100 keV deuterons to higher energies in the core of mixed D-3He plasmas at high concentrations of 3He. A large variety of fast-ion driven magnetohydrodynamic modes were observed, including the elliptical Alfvén eigenmodes (EAEs) with mode numbers n = −1 and axisymmetric modes with n = 0 in the frequency range of EAEs. The simultaneous observation of these modes indicates the presence of rather strong alpha-particle population in the plasma with a ‘bump-on-tail’ shaped velocity distribution. Linear stability analysis and Fokker–Planck calculations support the observations. Experimental evidence of the AEs excitation by fusion-born alpha-particles in the D-3He plasma is provided by neutron and gamma-ray diagnostics as well as fast-ion loss measurements. We discuss an experimental proposal for the planned full-scale D-T plasma experiments on JET based on the physics insights gained from these experiments.

The Joint European Torus (JET) gamma-ray camera has been recently upgraded with the installation of new gamma-ray detectors, based on LaBr3(Ce) scintillation crystals, which add spectroscopic capability to the existing system allowing measurements with good energy resolution (5% at 0.622 MeV), a dynamic range from hundreds of keV up to about 30 MeV, and high counting rate capabilities of MCps. First gamma-ray measurements during the C38 campaign of the JET have been successfully carried out, in particular, in D-3He plasmas from three-ion ion cyclotron resonance heating experiments, where the detection of 16.4 MeV γ-rays from D + 3He → γ + 5Li reactions with the gamma-ray camera upgrade allowed determining the spatial profile of alpha particles born in D + 3He fusion reactions.

This paper summarizes the physical principles behind the novel three-ion scenarios using radio frequency waves in the ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for ion cyclotron heating and fast-ion generation in multi-ion species plasmas. The theoretical section provides practical recipes for selecting the plasma composition to realize three-ion ICRF scenarios, including two equivalent possibilities for the choice of resonant absorbers that have been identified. The theoretical findings have been convincingly confirmed by the proof-of-principle experiments in mixed H-D plasmas on the Alcator C-Mod and JET tokamaks, using thermal He-3 and fast D ions from neutral beam injection as resonant absorbers. Since 2018, significant progress has been made on the ASDEX Upgrade and JET tokamaks in H-He-4 and H-D plasmas, guided by the ITER needs. Furthermore, the scenario was also successfully applied in JET D-He-3 plasmas as a technique to generate fusion-born alpha particles and study effects of fast ions on plasma confinement under ITER-relevant plasma heating conditions. Tuned for the central deposition of ICRF power in a small region in the plasma core of large devices such as JET, three-ion ICRF scenarios are efficient in generating large populations of passing fast ions and modifying the q-profile. Recent experimental and modeling developments have expanded the use of three-ion scenarios from dedicated ICRF studies to a flexible tool with a broad range of different applications in fusion research.

An integrated modelling methodology for the calculation of realistic plasma neutron sources for the JET tokamak has been developed. The computational chain comprises TRANSP plasma transport and DRESS neutron spectrum calculations, and their coupling to the MCNP neutron transport code, bridging plasma physics and neutronics. In the paper we apply the developed methodology to the analysis of neutron emission properties of deuterium and helium plasmas at JET, and validate individual modelling steps against neutron diagnostic measurements. Two types of JET discharges are modelled-baseline-like and three-ion radio-frequency scenarios-due to their diversity in plasma heating, characteristics of the induced fast ion population, and the imprint of these on neutron emission properties. The neutron emission modelling results are quantitatively compared to the total neutron yield from fission chambers, neutron emissivity profiles from the neutron camera, neutron spectra from the time-of-flight spectrometer, and neutron activation measurements. The agreement between measured and calculated quantities is found to be satisfactory for all four diagnostic systems within the estimated experimental and computational uncertainties. Additionally, the effect of neutrons not originating from the dominating D(D, n)He-3 reactions is studied through modelling of triton burnup DT neutrons, and, in mixed D-He-3 plasmas, neutrons produced in the Be-9(D, n gamma)B-10 reaction on impurities. It is found that these reactions can contribute up to several percent to the total neutron yield and dominate the neutron activation of samples. The effect of MeV-range fast ions on the neutron activation of In-115 and Al-27 samples is measured and computationally validated.

An understanding of fast (supra-thermal) ion behavior is of great importance in tokamak physics and is a subject studied from both theoretical and experimental perspectives. This paper investigates the spatial energy and density distributions of RF accelerated deuterons using the neutron camera at the tokamak JET. Using the 19 liquid scintillator detectors available in the neutron camera system, we obtain spatial information that cannot be accessed with a single sightline. We present a spectroscopic analysis method in which a spatially resolved model of the fast ion distribution is fitted to the pulse height spectra from all 19 detectors simultaneously. The fast ion distribution is parameterized in such a way that the density, energy, and pitch-angle parts are uncoupled. The energy part is composed of a Maxwellian distribution, characterized by an 'RF tail temperature,' and the spatial dependence is modeled as a two-dimensional Gaussian distribution on the poloidal plane of the tokamak. From this parameterized model, we can calculate the spectrum of fusion born neutrons originating from reactions involving RF accelerated deuterons, and by fitting this model to the measured neutron camera pulse height spectra, we obtain an estimate of the spatially resolved distribution of the fast deuterons. The method has been applied to three JET pulses using different RF heating schemes and is shown to identify several features of the fast ion distribution produced in the various scenarios. Hence, this method is able to provide quantitative information about the fast ion distribution resulting from different heating schemes, and can also be useful, e.g., to validate simulation results from RF modeling codes.

This paper summarizes the physical principles behind the novel three-ion scenarios using radio frequency waves in the ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for ion cyclotron heating and fast-ion generation in multi-ion species plasmas. The theoretical section provides practical recipes for selecting the plasma composition to realize three-ion ICRF scenarios, including two equivalent possibilities for the choice of resonant absorbers that have been identified. The theoretical findings have been convincingly confirmed by the proof-of-principle experiments in mixed H?D plasmas on the Alcator C-Mod and JET tokamaks, using thermal 3He and fast D ions from neutral beam injection as resonant absorbers. Since 2018, significant progress has been made on the ASDEX Upgrade and JET tokamaks in H?4He and H?D plasmas, guided by the ITER needs. Furthermore, the scenario was also successfully applied in JET D?3He plasmas as a technique to generate fusion-born alpha particles and study effects of fast ions on plasma confinement under ITER-relevant plasma heating conditions. Tuned for the central deposition of ICRF power in a small region in the plasma core of large devices such as JET, three-ion ICRF scenarios are efficient in generating large populations of passing fast ions and modifying the q-profile. Recent experimental and modeling developments have expanded the use of three-ion scenarios from dedicated ICRF studies to a flexible tool with a broad range of different applications in fusion research. AB - This paper summarizes the physical principles behind the novel three-ion scenarios using radio frequency waves in the ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexible ICRF technique for ion cyclotron heating and fast-ion generation in multi-ion species plasmas. The theoretical section provides practical re, The authors are grateful to the anonymous reviewers for their constructive comments that allowed us to improve the paper, I. Voitsekhovitch for her valuable comments and suggestions during the paper preparation, and to H. Meyer and J. Faustin for fruitful discussions. We thank the ITPA Energetic Particle Physics Topical Group for its support. 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 and 2019–2020 under Grant Agreement No. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Part of this work was also carried out in the framework of projects done for the ITER Scientist Fellow Network (ISFN). ITER is the Nuclear Facility INB No. 174. The views and opinions expressed herein do not necessarily reflect those of the ITER Organization. This publication is provided for scientific purposes only. Its contents should not be considered as commitments from the ITER Organization as a nuclear operator in the frame of the licensing process., Peer Reviewed, "Article signat per 67 autors/es: Ye. O. Kazakov, J. Ongena, J. C. Wright, S. J. Wukitch, V. Bobkov, J. Garcia, V. G. Kiptily, M. J. Mantsinen, M. Nocente, M. Schneider, H. Weisen, Y. Baranov, M. Baruzzo, R. Bilato, A. Chomiczewska, R. Coelho, T. Craciunescu K. Crombé, M. Dreval, R. Dumont, P. Dumortier, F. Durodié, J. Eriksson, M. Fitzgerald, J. Galdon-Quiroga, D. Gallart, M. Garcia-Muñoz, L. Giacomelli, C. Giroud, J. Gonzalez-Martin, A. Hakola, P. Jacquet, T. Johnson, A. Kappatou, D. Keeling, D. King, K. K. Kirov, P. Lamalle, M. Lennholm, E. Lerche, M. Maslov, S. Mazzi, S. Menmuir, I. Monakhov5, F. Nabais, M. F. F. Nave, R. Ochoukov, A. R. Polevoi, S. D. Pinches, U. Plank, D. Rigamonti, M. Salewski, P. A. Schneider, S. E. Sharapov, Ž. Štancar, A. Thorman, D. Valcarcel, D. Van Eester, M. Van Schoor, J. Varje, M. Weiland, N. Wendler, JET Contributors, ASDEX Upgrade Team, EUROfusion MST1 Team, and Alcator C-Mod Team", Postprint (published version)

Dedicated experiments to generate energetic D ions and D-(3) He fusion-born alpha particles were performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Using the 3-ion D-(D-NBI)-(3) He radio frequency (RF) heating scenario, deuterium ions from neutral beam injection (NBI) were accelerated in the core of mixed D-(3) He plasmas to higher energies with ion cyclotron resonance frequency (ICRF) waves, in turn leading to a core-localized source of alpha particles. The fast-ion distribution of RF-accelerated D-NBI ions was controlled by varying the ICRF and NBI power (P-ICRF approximate to 4-6 MW, P-NBI approximate to 3-20 MW), resulting in rather high D-D neutron (approximate to 1x10(16) s(-1)) and D-(3) He alpha rates (approximate to 2x10(16) s(-1)) at moderate input heating power. Theory and TRANSP analysis shows that large populations of co-passing MeV-range D ions were generated using the D-(D-NBI)-(3) He 3-ion ICRF scenario. This important result is corroborated by several experimental observations, in particular gamma-ray measurements. The developed experimental scenario at JET provides unique conditions for probing several aspects of future burning plasmas, such as the contribution from MeV range ions to global confinement, but without introducing tritium. Dominant fast-ion core electron heating with T-i approximate to T-e and a rich variety of fast-ion driven Alfven eigenmodes (AEs) were observed in these D-(3) He plasmas. The observed AE activities do not have a detrimental effect on the thermal confinement and, in some cases, may be driven by the fusion born alpha particles. A strong continuous increase in neutron rate was observed during long-period sawteeth (>1 s), accompanied by the observation of reversed shear AEs, which implies that a non monotonic q profile was systematically developed in these plasmas, sustained by the large fast-ion populations generated by the 3-ion ICRF scenario.

Dedicated experiments were conducted in mixed H-D plasmas in JET to demonstrate the efficiency of the 3-ion ICRF scenario for plasma heating, relying on injected fast NBI ions as the resonant ion component. Strong core localization of the RF power deposition in the close vicinity of the ion-ion hybrid layer was achieved, resulting in an efficient plasma heating, generation of energetic D ions, strong enhancement of the neutron rate and observation of Alfvenic modes. A consistent physical picture that emerged from a range of fast-ion measurements at JET, including neutron and gamma-ray measurements, a high-energy neutral particle analyzer and MHD mode localization analysis, is presented. The possibility to moderate the fast-ion energies with the ratioP(ICRF)/P(NBI)and the choice of the NBI injectors is demonstrated. An outlook of possible applications of the 3-ion scenarios, including a recent example of its use in mixed D-He-3 plasmas in JET and promising scenarios for D-T plasmas, are presented.

Dedicated experiments to generate energetic D ions and D-3 He fusion-born alpha particles were performed at the Joint European Torus (JET) with the ITER-like wall (ILW). Using the 3-ion D-(DNBI)-3 He radio frequency (RF) heating scenario, deuterium ions from neutral beam injection (NBI) were accelerated in the core of mixed D3He plasmas to higher energies with ion cyclotron resonance frequency (ICRF) waves, in turn leading to a core-localized source of alpha particles. The fast-ion distribution of RF-accelerated D-NBI ions was controlled by varying the ICRF and NBI power (PICRF 4-6 MW, PNBI ≈ 3-20 MW), resulting in rather high D-D neutron (≈ 1 × 1016 s-1) and D-3He alpha rates (≈ 2 × 1016 s-1) at moderate input heating power. Theory and TRANSP analysis shows that large populations of co-passing MeV-range D ions were generated using the D-(DNBI)-3He 3-ion ICRF scenario. This important result is corroborated by several experimental observations, in particular gamma-ray measurements. The developed experimental scenario at JET provides unique conditions for probing several aspects of future burning plasmas, such as the contribution from MeV range ions to global confinement, but without introducing tritium. Dominant fast-ion core electron heating with Ti ≈ Te and a rich variety of fast-ion driven Alfvén eigenmodes (AEs) were observed in these D-3 He plasmas. The observed AE activities do not have a detrimental effect on the thermal confinement and, in some cases, may be driven by the fusion born alpha particles. A strong continuous increase in neutron rate was observed during long-period sawteeth (>1 s), accompanied by the observation of reversed shear AEs, which implies that a non monotonic q profile was systematically developed in these plasmas, sustained by the large fast-ion populations generated by the 3-ion ICRF scenario.

Dedicated experiments were conducted in mixed H-D plasmas in JET to demonstrate the efficiency of the 3-ion ICRF scenario for plasma heating, relying on injected fast NBI ions as the resonant ion component. Strong core localization of the RF power deposition in the close vicinity of the ion-ion hybrid layer was achieved, resulting in an efficient plasma heating, generation of energetic D ions, strong enhancement of the neutron rate and observation of Alfvenic modes. A consistent physical picture that emerged from a range of fast-ion measurements at JET, including neutron and gamma-ray measurements, a high-energy neutral particle analyzer and MHD mode localization analysis, is presented. The possibility to moderate the fast-ion energies with the ratio PICRF/PNBI and the choice of the NBI injectors is demonstrated. An outlook of possible applications of the 3-ion scenarios, including a recent example of its use in mixed D-3 plasmas in JET and promising scenarios for D-T plasmas, are presented.

We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed 'three-ion' scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3 He ions to high energies in dedicated hydrogen-deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3 He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3 He-rich solar flares.