[en] Technique scheme of plasma probing by heavy ion beams and procedure for trajectory calculation and determination of configuration and sizes of the investigated region are presented. Problem statements of experiment conditions optimization of plasma probing by heavy particle beams are discussed. Examples of optimization problem solutions for different tokamak and stellarator conditions are presented. Values of probing beams main parameters are determined, different schemes of experiment with account of modern equipment potentialities are suggested

[en] We discuss the specific features of the application of heavy ion beam probe (HIBP) systems to tight aspect ratio tokamaks. We present and compare the HIBP projects for the TUMAN-3, GLOBUS, and COMPASS, where the inner part of the plasma is not available for regular chord diagnostics, so the HIBP becomes very desirable. All existing tight aspect ratio facilities and projects have a low (less than 1.9 T) toroidal field that requires a comparatively low beam energy range. The natural elongation and triangularity in tight aspect ratio tokamaks require an accurate calculation of the three-dimensional magnetic field for probing optimization. In comparison with traditional tokamaks, the detector grids have a wider energy interval. In general, the trajectories and detector grids for tight aspect ratio tokamaks become similar to the stellarator ones. Traditional and new probing schemes are suggested and discussed. copyright 1997 American Institute of Physics

No abstract available

No abstract available

[en] For the investigation of the plasma density and potential in the TJ-1 tokamak, we applied the heavy ion beam probe (HIBP) diagnostics with the beam energy up to 100 keV. The geometry of the experiment allows us to observe the whole plasma cross section and to catch the primary beam for direct calibration. HIBP on TJ-1 operates in two modes: shot-by-shot measurements which allow us to obtain the time evolution of the plasma parameters at every desired point of the detector grid, and scanning along the detector line (generally passing through the center) in the single shot which allows us to get a few profiles of the plasma parameters. When scanning we varied the injection angle with a period less than 2 ms. The spatial resolution of measurements was 2 endash 5 mm. The bandwidth used (∼20 kHz) allows us to see the slow oscillations of the potential and density. The measurements were performed in the regimes with the magnetic field B=1.1 endash 1.4 T, current I=26 endash 32 kA, and the shot duration up to 25 ms. HIBP on TJ-1 enables us to measure simultaneously the time-spatial evolution of the potential and density; that makes HIBP a powerful tool for direct investigation of the transport processes in the plasma driven by the radial electric field. copyright 1997 American Institute of Physics

[en] This paper reports the heavy ion beam probe study of the regimes with electron internal transport barriers obtained by off-axis ECRH/ECCD (140 GHz, 0.5-0.8 MW) with B=2.1-2.14 T, I_p=200-330 kA, q_lim=2.4[5]. We investigate the extra potential values with respect to initial steady state phase (L-mode). The time evolution of the extra potential profile was obtained by the periodical scan of the beam injection angle. The power supply system provides the 7 ms scan every 20 ms

[en] Specific oscillations within a range of 20 kHz ('20 kHz-mode') were investigated on the T-10 and TEXT tokamaks using Heavy Ion Beam Probe (HIBP) diagnostic. Regimes with ohmic heating on both machines, and with off-axis ECRH in T-10 were studied. It was shown that '20 kHz-modes' are mainly the potential oscillations. The power spectrum of the oscillations has the form of a solitary quasi-monochromatic peak with a contrast range of (3-5). They are the manifestation of torsional plasma oscillations with poloidal wavenumber m=0, called zonal flows. It was shown that in TEXT the radial electric field oscillations exist in a limited radial range of 0.65<ρ<0.95. The frequency of '20 kHz-mode' varies with local T_e: f∼T_e^1/2, which is consistent with theoretical scaling for geodesic acoustic modes (GAM): f_GAM∼c_s/R∼T_e^1/2, where c_s is the speed of sound. The absolute frequencies are close to GAM values within a factor of unity. (author)