V. V. Prikhodko

Progress in Mirror-Based Fusion Neutron Source Development

The Budker Institute of Nuclear Physics in worldwide collaboration has developed a project of a 14 MeV neutron source for fusion material studies and other applications. The projected neutron source of the plasma type is based on the gas dynamic trap (GDT), which is a special magnetic mirror system for plasma confinement. Essential progress in plasma parameters has been achieved in recent experiments at the GDT facility in the Budker Institute, which is a hydrogen (deuterium) prototype of the source. Stable confinement of hot-ion plasmas with the relative pressure exceeding 0.5 was demonstrated. The electron temperature was increased up to 0.9 keV in the regime with additional electron cyclotron resonance heating (ECRH) of a moderate power. These parameters are the record for axisymmetric open mirror traps. These achievements elevate the projects of a GDT-based neutron source on a higher level of competitive ability and make it possible to construct a source with parameters suitable for materials testing today. The paper presents the progress in experimental studies and numerical simulations of the mirror-based fusion neutron source and its possible applications including a fusion material test facility and a fusion-fission hybrid system.

Formation of a Narrow Radial Density Profile of Fast Ions in the GDT Device

The radial density profile of fast ions with a mean energy of 10 keV is measured in experiments with a two-component high-β plasma in the GDT device. Fast ions are produced by injecting neutral beams into a warm plasma. The measured fast-ion density profile is found to be narrower than that calculated with allowance for the neutral beam trapping and Coulomb scattering. Special experiments with a movable limiter have indicated that the formation of a narrow fast-ion density profile in GDT cannot be attributed to the loss of fast ions. Possible mechanisms responsible for this effect are discussed.

Mirror based fusion neutron source: Current status and prospective

The paper presents a recent progress in experimental studies and status of numerical simulations of the mirror based fusion neutron source developed by the Budker Institute of Nuclear Physics (Novosibirsk, Russia) and its possible applications including a fusion material test facility and a fusion-fission hybrid system. Current research activity is supported by the Russian Science Foundation (project N 14-50-00080).

Project of the GDT-based steady-state experiment

In recent years, significant success in a plasma stabilization, heating and confinement in Gas Dynamic Trap (GDT) has been acheived. However, transition processes such as fast ions buildup, ion and electron temperature growth, etc., are still underway until the end of plasma heating. Thus, heating sources worktime (around 5 ms) is too short for plasma parameters to become stationary. In this work we propose a project of GDT-based stationary plasma experiment with pulse length long enough to finish all transition processes. The implemetation of the project will allow us to test GDT stabilization, heating and confinement methods to stationary conditions and to scale the methods to reactor-sized devices. Features of the project include a superconducting magnetic system with 15 T magnetic mirror field, 30 ms plasma pulse and mixed neutral particle and ECR heating. Results of numerical simulations of such experiment using DOL code are also presented.

Recent Calculation Results for a Fission-Fusion System with Gas Dynamic Trap Neutron Source

Budker Institute of Nuclear Physics SB RAS together with Nuclear Safety Institute RAS is working on a hybrid system with a neutron source based on the gas-dynamic trap (GDT) and sub-critical blanket for incineration of high-activity long-lived radioactive wastes. This report gives an overview of recent results obtained in collaborative development of modeling tools for the described system. Particularly, DOL code was created for the source plasma parameters calculation, NMC code was applied to model neutron transport processes and NMC+ module was developed for burnup calculations. The codes are shortly described in the article. Validation results are also presented.

Study of Microinstabilities in Anisotropic Plasmoid of Thermonuclear Ions

Abstract The following work presents the results of investigation of microinstabilities in the anisotropic synthesized hot ion plasmoid (SHIP). Plasmoid is located in a small mirror section that is installed at one side of the GDT facility, which is an axially symmetric magnetic mirror device of gas dynamic trap type. To define the type and the parameters of the developing microinstability a set of high-frequency electrostatic and magnetic probes was used. The microinstability observed in the additional section of GDT is the Alfven ion cyclotron instability (AIC), because of small azimuthal wave numbers, magnetic field vector rotating in the direction of ion gyration and oscillation frequency below the actual ion cyclotron frequency. AIC instability threshold was registered at the following plasma parameters: fast ion density n > 3 × 1013 cm-3, ratio of ion pressure to magnetic field pressure β ≈ 0.02, anisotropy A = 40, ai/Rp ≈ 0.23, where ai is the ion gyroradius and Rp is the plasmoid radius.

Low-Frequency Oscillations of Plasma in the Gas Dynamic Trap

Abstract Vortex confinement is a new and effective method of convective losses suppression in gas-dynamic trap. Low frequency oscillations of radial magnetic field were observed during study of plasma MHD activity. Experimental data confirm the main statements of the vortex confinement theory. We also observed displacement of fast ions turning point. It can be explained by high beta equilibrium effects.