The paper presents a fusion plant concept called VOYAGER developed by leading groups in fusion research (BINP SB RAS) and high-temperature superconductivity (SuperOx LLC). This plant has an open trap configuration with high-temperature superconducting (HTS) vortex (helical) magnets for plasma confinement. The plant is designed with deuterium-deuterium fusion in the ignited regime (without external plasma heating) providing an unlimited supply of reactor fuel, using already proven technologies, and thus maximising the plant's electrical power output and revenue. The costs for construction and operation of the power plant, as well as levelised cost of electricity (LCOE) for the plant, are calculated. The VOYAGER plant has comparable construction and operating costs with existing fusion plant projects; however, VOYAGER, due to the high electrical power output, has the lowest LCOE. The low LCOE value for the proposed plant makes it competitive with conventional electricity sources. Reduced research and development costs due to the use of proven technologies and modular nature of open trap confinement make VOYAGER an even more attractable preposition among fusion plant concepts.

Since the last IAEA-FEC in 2021, significant progress on the development of long pulse steady state scenario and its related key physics and technologies have been achieved, including the reproducible 403 s long-pulse steady-state H-mode plasma with pure radio frequency (RF) power heating. A thousand-second time scale (similar to 1056 s) fully non-inductive plasma with high injected energy up to 1.73 GJ has also been achieved. The EAST operational regime of high beta(P) has been significantly extended (H-98y2 > 1.3, beta(P) similar to 4.0, beta(N) similar to 2.4 and n(e)/n(GW) similar to 1.0) using RF and neutral beam injection (NBI). The full edge localized mode suppression using the n = 4 resonant magnetic perturbations has been achieved in ITER-like standard type-I ELMy H-mode plasmas with q(95) approximate to 3.1 on EAST, extrapolating favorably to the ITER baseline scenario. The sustained large ELM control and stable partial detachment have been achieved with Ne seeding. The underlying physics of plasma-beta effect for error field penetration, where toroidal effect dominates, is disclosed by comparing the results in cylindrical theory and MARS-Q simulation in EAST. Breakdown and plasma initiation at low toroidal electric fields (<0.3 V m(-1)) with EC pre-ionization is developed. A beneficial role on the lower hybrid wave injection to control the tungsten concentration in the NBI discharge is observed for the first time in EAST suggesting a potential way toward steady-state H-mode NBI operation.

A short review of the studies carried out at the Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences (BINP SB RAS) on the photon neutralization of the beams of negative ions is presented. The principal distinctive feature of the presented approach consists in the nonresonant accumulation of photons in a limited space. Their confinement is based on the adiabatic motion of photons in a system of concave mirrors, which is insensitive to the quality of the injected radiation. An analysis is carried out of the possibility of using the neutralizer based on such a nonresonant photon trap in large-scale installations such as ITER and TRT, and a future experiment is described on the photon neutralization using a beam of negative hydrogen ions with energy up to 130 keV and a current of about 10 mA.

This paper highlights the most important results achieved at the spherical tokamak Globus-M2 with a high magnetic field. This paper also covers the most important topics of fusion research: thermal energy confinement in regimes with neutral beam injection, toroidal Alfvén eigenmode and correspondent fast ions confinement issues, L-H transition, turbulence suppression and edge-localized modes' behavior, experimental and theoretical study of regimes with nitrogen seeding that allow to significantly reduce thermal loads on the divertor plates, and experiments and simulations of lower hybrid current drive. The research results provide the basis for the next step toward a fusion neutron source—the development of the Globus-3 spherical tokamak.

An overview of the neutral beam injectors developed at the Budker Institute of Nuclear Physics in Novosibirsk during the last 10 years is presented. These neutral injectors are used for plasma diagnostics, heating and current drive in modern fusion devices with magnetic confinement. An arc or a radio-frequency (RF) discharge generates a plasma in the ion sources of the injectors, and a positive hydrogen or deuterium ion beam is extracted and accelerated by a multiaperture ion-optical system (IOS). The accelerated ion beam is converted into a neutral one in a gas target. The precision multiaperture IOS with spherically concave electrodes provides ballistic focusing of the neutral beam. The high-energy, high-power beam injector based on negative ions, which is currently under development, is described as well. It comprises a RF negative ion source and a wide-aperture electrostatic accelerator separated from the source by a low-energy beam transport line, thereby improving the injector reliability.

The receiver calorimeter (RC) is one of the main elements of the beam path of an atomic beam injector with ballistic focusing. A water-cooled RC developed for an injector of a focused beam of fast deuterium atoms with a beam power of more than 1 MW and pulse duration of 2 s [1] installed at the variable configuration tokamak (TCV) in Lausanne (Switzerland) is considered. The design of the RC includes receiving plates with liquid flow swirlers installed in them to enhance heat transfer and pipe-in-pipe collectors of water inlet and water outlet that provide the movement into a vacuum. These technical solutions made it possible to achieve good energy efficiency of the device with very small overall dimensions and mass flow of the coolant. The design of the main elements of the calorimeter is described. The results of simulation of the coolant flow and heat transfer and some experimental data are presented.

A source of negative hydrogen ions based on the recharging of a beam of positive ions in a gas target is being developed at the Institute of Nuclear Physics. G.I. Budker SB RAS. The charge exchange source can be used to inject into the tandem accelerator a neutron source intended for boron neutron capture therapy. One of the important elements of the source is the plasma emitter, which creates positive ions for primary acceleration. As an emitter, a high-frequency driver based on an induction discharge and designed for a multi-second operating mode was chosen. In this work, we measured the emission characteristics of a high-frequency driver using a moving grid probe. As a result, the parameters necessary for the use of the driver in a rechargeable source of negative ions have been achieved. The analysis of experimentally measured thermal loads in the multisecond mode is carried out.

Atomic beam injection is one of the main methods of plasma heating in thermonuclear facilities. An injector of high-energy hydrogen atoms for plasma heating based on the acceleration and neutralization of negative hydrogen ions is being developed at the Budker Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences. The injector uses a surface plasma source, in which a plasma flow is created using a radio-frequency driver: an induction radio-frequency (RF) discharge, ignited inside a cylindrical ceramic chamber when an RF voltage is applied to an external antenna. As a part of this work, a new version of the RF driver is being developed. A protective screen is used to prevent overheating and erosion of the ceramic wall of the driver. The operation of RF driver with different protective screens is studied. These screens reduce the efficiency of RF power transmission into the discharge, but make it possible the operation of the ion source in multi-second or steady-state pulses.

The paper describes the conceptual design of a small-scale experiment within the fusion neutron source project ALIANCE (Axisymmetric LInear Advanced Neutron sourCE). The experimental machine is an axially symmetric magnetic plasma trap with a high mirror ratio, which focuses on the physical and engineering problems of mirror-based gasdynamic neutron sources. The specific research topics covered include the magnetohydrodynamic (MHD) stability of plasmas with high mirror ratios, the operation of the electrodes used for plasma stabilization, and problems related to particle and energy transport. ALIANCE-T features superconducting mirror solenoids that enable it to reach mirror ratios of ∼100 and a helicon plasma source with a power of up to 25 kW installed directly in the confinement zone between the mirrors. The expected plasma parameters are estimated using a simple analytical model, which takes into account gasdynamic axial plasma losses, cross-field transport, and the interaction of the plasma with neutral gas. It is projected that the machine will simultaneously achieve a plasma density >1013 cm−3 and a temperature >10 eV in a continuous discharge lasting for 1–8 h. This paper gives a detailed description of the key machine subsystems and introduces the analytical model used for calculation of the plasma parameters.

Results of experiments on a linear facility with a helicon plasma source operating at a frequency of 13.56 MHz and a power of up to 15 kW are reported. In the experiments, different antennas (coil, NAGOYA TYPE III, and half-wave helicon) with azimuthal wavenumbers of m = 0, ±1 were used. Plasma density and electron temperature radial profiles for antennas of these types were measured as a function of the magnetic field under the antenna and the gas pressure. The maximum plasma density obtained in the experiments was 2 × 1013 cm–3 at a magnetic field of ~200 G.

A negative ion source, which utilizes a conversion of primary high current proton beam into negative ions in a gas target via charge-exchange collisions, is under development in Budker Institute, Novosibirsk. The proposed beam will be used for injection into a tandem accelerator, which is a part of the neutron source dedicated for boron-neutron capture therapy (BNCT). The ion source is designed to produce a beam that contains ≥50% of molecular ions. The initial ion beam current is about 1 A at 30 keV energy. After molecular ion dissociation in a gas target, which produces protons with an energy of 15 keV, and further charge-exchange collisions, the beam after the target will contain about 2% of negative ion species with a current in excess of 10 mA. The negative ion beam is then separated by the magnetic field, accelerated up to an energy of 105 keV and enters the tandem accelerator. This paper presents the results of simulations of the beam formation, acceleration and transport. The arrangement of the ion source and corresponding high voltage power supply are also discussed.

A high-voltage negative ion based neutral beam injector is under construction at the Budker Institute of Nuclear Physics. It consists of a negative ion source, a Low Energy Beam Transport section (LEBT), which purifies the beam before acceleration, a multi-electrode single-aperture beam accelerator, a negative ion neutralizer and a magnetic separator with beam energy recuperators. The test stand to study the main injector components, consisting of the negative ion source and LEBT, the high voltage platform and the accelerator with beam transport section was launched in 2019. The initial experiments on the negative ion beam production, acceleration and 180 keV transport were tested. The power load to the acceleration tube electrodes and the data on the transported beam parameters, measured at the several positions and at the beam dump calorimeter are presented. The beam transport efficiency as a function of various ion source and LEBT parameters are presented and discussed.

Helicon plasma source is being developed at the Budker Institute of Nuclear Physics SB RAS, Novosibirsk. The parameters are studied of the plasma confined in a mirror trap configuration of the magnetic field at an operating frequency of 13.56 MHz. For matching the antenna impedance and generator load, the Π-type matching box was designed and successfully tested at powers of 20–25 kW. The low reflected power (1–2%) was obtained, as compared to that for the L-type matching network used previously (the reflected power was more than 15% at the generator output power of 18 kW). The triple Langmuir probe is used to determine the plasma density. The plasma resistive characteristics were determined using the Rogowski coil measuring the RF antenna current. In the experiments, the plasma with a density of ∽5⋅1012 cm-3 and an electron temperature on axis of 10 eV was obtained, and the RF power transfer efficiency was ∽85% at the RF power of 25 kW.

A prototype of a powerful high-voltage neutral beam injector, based on acceleration of negative hydrogen ions and their neutralization, is under development at Budker Institute of Nuclear Physics (BINP). The design of the BINP high-voltage injector includes several innovative components, important for injector operation stability and overall efficiency. It includes a multi-aperture long-pulse surface-plasma negative ion source with thermostabilized grid, ithe magnetic system with concaved field lines in the ion-optic system (IOS) and the distributed cesium deposition system. The injector scheme incorporates a wide-aperture low-energy beam transport (LEBT) section, plasma target for negative ionneutralization, and recuperators of non-neutralized ions. Several test stands were constructed at BINP for injector component studies. This paper describes the results of experiments on negative ion beam production, transport through LEBT, ion acceleration to energy up to 240 keV and transport through the high voltage beam transport (HEBT) section to the distance ∼10 m from the source. The parameters of the transported beam, which were measured at several points along the beam line and at the beam dump calorimeter, are presented. The beam transport efficiency as a function of various ion source, LEBT and HEBT parameters is measured and compared with the calculated values. The results dof plasma neutralization target study are presented as well.