Abstract
The COMPASS tokamak (R = 0.56 m, a = 0.23 m, I < 400 kA) is equipped with two identical neutral beam injectors (NBI) manufactured by the Budker Institute of Nuclear Physics, Novosibirsk. Each of them produces the neutral beam with a power up to 400 kW at energies of up to 40 keV.
This beam is injected into the tokamak chamber by a narrow beam duct where a part of the injected power is lost by a beam clipping. The injected power can be estimated using the geometry arrangement and the beam parameters.
These calculations are compared with an absorbed power by the plasma which is obtained from the plasma power balance. Then, the global energy confinement time of ohmic and NBI heated discharges is determined and compared with previous results on the COMPASS-D tokamak in the Culham laboratory.