IAP/RAS, Nizhny Novgorod, Russia
GISMO, a CW high-current quasi-gasdynamic ECR ion source, is under development at the IAP RAS. The quasi-gasdynamic confinement regime, featuring high plasma density (up to 1014 cm-3) and moderate electron temperature (~100 eV), allowed to extract pulsed beams of H+ and D+ ions with current of 450 mA and RMS emittance <0.07 pi mm mrad*. It has been already demonstrated that major benefits of quasi-gasdynamic confinement, previously tested in pulsed mode, are scalable to the CW operational mode. In first experiments at GISMO facility, the ion beams were extracted in pulsed mode from the CW plasma of ECR discharge due to technical limitations of cooling circuits. Proton beams with current up to 70 mA were achieved at extraction voltage of 40 kV. A new unique extraction system especially effective for the formation of high current density ion beams was developed.
* V. Skalyga, I. Izotov, S. Razin, A. Sidorov, S. Golubev, T. Kalvas, H. Koivisto, and O. Tarvainen. Review of Scientific Instruments 85, 02A702 (2014); https://doi.org/10.1063/1.4825074
IAP/RAS, Nizhny Novgorod, Russia
Sources of dense plasma fluxes with wide aperture are extensively used in applied science, i.e. surface treatment, and as a part of neutral beam injectors. ECR discharge in a solenoidal magnetic field (i.e. with no magnetic mirrors for plasma confinement), sustained by a powerful radiation of modern gyrotrons is under consideration at IAP RAS as a possible alternative to widely used vacuum arc, RF and helicon discharges. The use of a high frequency radiation (37.5 GHz) allows to obtain a discharge at lower pressure, sustain almost fully ionized plasma with density more than 1013 cm-3, whereas the power on the level of several hundreds of kW allows one to create such a plasma in considerably large volume. In the present work fluxes of hydrogen plasma with the equivalent current density of 750 mA/cm2 and the total current of 5 A were obtained. A multi-aperture multi-electrode extraction system design capable of forming the non-divergent ion beam was developed with the use of IBSimu code.