Physical and technical details of the GOL-NB project are presented. GOL-NB is a medium-scale multiple-mirror trap that is under development in the Budker Institute, Novosibirsk, Russia. This device will be created in several years as a deep conversion of the existing GOL-3 facility. It will consist of a central trap with two 0.75 MW neutral beams, two multiple-mirror solenoids, two expander tanks and a plasma gun that creates the start plasma. The central trap with the neutral beam injection-heated plasma is a compact gas-dynamic system. The multiple-mirror sections should decrease the power and particle losses along the magnetic field. The confinement improvement factor depends on plasma parameters and on the magnetic configuration in the multiple mirrors. The main physical task of GOL-NB is direct demonstration of the performance of multiple-mirror sections that will change equilibrium plasma parameters in the central trap. In this paper we discuss results of the scenario modeling and progress in the hardware.

The first plasma campaign was completed in a start configuration of the GOL-NB multiplemirror trap. The device included a 4 m long high-field section, two end sections of magnetic flux expanders and a short temporary section for the commissioning of two 25 keV, 0.75 MW neutral beams. Low-temperature start plasma was created using a coaxial arc plasma gun. The main objective of the first experiments is to develop and characterize the low-temperature plasma stream that will be used later for filling the central trap of GOL-NB with the start plasma. The plasma parameters and operation regimes are reported.