IAP/RAS, Nizhny Novgorod, Russia
This work is a continuation of the experiments described in [1, 2] and aimed at the investigation of the new conceptions of MHD stabilization of plasma in open axisymmetric traps, specifically, it is aimed at the investigation of the shear flow influence on the transport control in open mirror traps. As in previous experiments, shear flow was created by limiter-electrode with bias potential according to the vacuum chamber. Plasma density structure in radial and azimuthal directions was studied. Mode structure of the perturbations was investigated. Substantial sharp shift of the plasma density maximum to the system axis with bias potential growth was demonstrated. It was shown, that the value of the bias potential that corresponds to the plasma density profile shift grows with the magnetic field growth that can be interpreted as the electron temperature growth. Some theoretical estimations of the influence of the transversal losses decrease on plasma parameters were made.
[1] A.Sidorov, P.Bagryansky, A.Beklemishev et al. Trans. Fusion Sci. and Technology, 59, 112, (2011).
[2] I.Izotov, S.Razin, A.Sidorov et al. Rev. Sci. Instrum., 83, 02A318 (2012).
IAP/RAS, Nizhny Novgorod, Russia
JYFL, Jyväskylä, Finland
Operation of modern high power accelerators often requires production of intense beams of hydrogen ions. Newer facilities aiming at outperforming the previous generation accelerators are usually designed for higher beam currents. Meeting the demand for hydrogen ion beams with higher intensity and low transverse emittance is, therefore, becoming increasingly difficult problem. Present work is devoted to experimental investigation of proton beams production from dense plasma (Ne>1013 cm-3) of ECR discharge sustained by 37.5 GHz, 100 kW gyrotron radiation at SMIS 37 facility at IAP RAS. Different extraction system configurations were used. It was demonstrated that ultra bright proton beam with 4.5 mA current and 0.1 π·mm·mrad normalized emittance (brightness=45 A/(π·mm·mrad)2) can be formed with 1-hole (1 mm in diameter) extraction. For production of high current beams a 13-hole extractor was used. 200 mA and 1.1 π·mm·mrad normalized emittance proton beam was obtained. A possibility of further beam parameters enhancement by developing of extraction system and its power supply is discussed. It was shown that in generated proton beams H2+ component was less than 6%.