HIBP diagnostics on T-10

Abstract

A heavy ion beam probe diagnostic was installed on T-10 tokamak. Cs+ and Tl+ beams with the energy loo-280 keV and intensity about a few dozen ,uA were used. The diagnostic is able to make two-dimensional measurements of plasma parameters along the detector line, The detector grid covered the first quadrant of the plasma cross section. The measurements are possible with r/a=0.3-1, and o=O"-90" for B=lS T and Cs+ ions. High-voltage stabilizers keep the analyzer and accelerator voltage drift on the level A U/U-10m5. An absolute in situ calibration of the energy analyzer, using He target will allow to make a more accurate absolute referencing of the potential. The time dependence of the local plasma parameters was obtained. A scan along the detector line by variation of injection angle and obtaining the whole profile during one pulse is possible. The diagnostic is also sensitive to poloidal magnetic field. 0 1995 American Institute of Physics.

Plasma Potential in Toroidal Devices: T-10, TJ-II, CHS and LHD

“…The Heavy Ion Beam Probe (HIBP) is a unique diagnostic to study directly the electric potential and turbulence characteristics in toroidal plasmas from the core to the edge [2,3]. The HIBP was used in the T-10 circular tokamak [4], in TJ-II, a four-period flexible heliac with helical plasma axis [5] and in the stellarators CHS [6] and LHD [7] to study the potential with high spatial (< 1 cm) and temporal (1 µs) resolution in plasmas with comparable parameters, but in different magnetic configurations. Comparison for Ohmic (OH) and Electron Cyclotron Resonance Heating (ECRH) plasmas in the two machines, T-10 and TJ-II reveals similar tendencies of the potential profiles [8,9].…”

Study of the plasma potential evolution during ECRH in the T-10 tokamak and TJ-II stellarator

“…The last mirror of the quasi-optical microwave transmission line is located inside the vacuum vessel and allows current drive up to 1 kA. The HIBP diagnostics used Cs + ions with beam energy in the range (100-125) keV [6].…”

“…To probe the plasma core, Tl + ions were accelerated up to 250 kV [6]. The recent modification of the beamlines and the entrance ports expands the HIBP observation area.…”

Heavy Ion Beam Probing - The Diagnostics For Internal Measurements Of The Plasma Electric Potential And Turbulence In Toroidal Plasma Devices

“…HIBP was first introduced in 1970s [3], it was later developed to the multichannel version to study the turbulent particle flux [4]. This report presents the further HIBP development and application to the T-10 tokamak [5] (a=0.3 m, R=1.5 m, B t =1.5-2.4 T, I p =140-330 kA, P ECRH <1.2 MW) and TJ-II stellarator [6] (<a>=0.22 m, <R>=1.5 m, B t =1 T, P ECRH 0.6 MW, P NBI 1 MW). It discusses the diagnostics capabilities and limitations and also presents the examples of recent measurements of plasma potential and turbulence characteristics.…”