High current proton beams production at Simple Mirror Ion Source 37 Skalyga, V.; Izotov, I.; Razin, S.; Sidorov, A.; Golubev, S.; Kalvas, Taneli; Koivisto, Hannu; Tarvainen, Olli Skalyga, V., Izotov, I., Razin, S., Sidorov, A., Golubev, S., Kalvas, T., . . . , & Tarvainen, O. (2014 This paper presents the latest results of high current proton beam production at Simple Mirror Ion Source (SMIS) 37 facility at the Institute of Applied Physics (IAP RAS). In this experimental setup, the plasma is created and the electrons are heated by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap fulfilling the ECR condition. Latest experiments at SMIS 37 were performed using a single-aperture two-electrode extraction system. Proton beams with currents up to 450 mA at high voltages below 45 kV were obtained. The maximum beam current density was measured to be 600 mA/cm 2 . A possibility of further improvement through the development of an advanced extraction system is discussed. © 2013 AIP Publishing LLC.

New progress of high current gasdynamic ion source (invited) Skalyga, V.; Izotov, I.; Golubev, S.; Sidorov, A.; Razin, S.; Vodopyanov, A.; Tarvainen, Olli; Koivisto, Hannu; Kalvas, Taneli Skalyga, V., Izotov, I., Golubev, S., Sidorov, A., Razin, S., Vodopyanov, A., . . . Kalvas, T. (2016). New progress of high current gasdynamic ion source (invited The experimental and theoretical research carried out at the Institute of Applied Physics resulted in development of a new type of electron cyclotron resonance ion sources (ECRISs)-the gasdynamic ECRIS. The gasdynamic ECRIS features a confinement mechanism in a magnetic trap that is different from Geller's ECRIS confinement, i.e., the quasi-gasdynamic one similar to that in fusion mirror traps. Experimental studies of gasdynamic ECRIS were performed at Simple Mirror Ion Source (SMIS) 37 facility. The plasma was created by 37.5 and 75 GHz gyrotron radiation with power up to 100 kW. High frequency microwaves allowed to create and sustain plasma with significant density (up to 8 × 10 13 cm −3 ) and to maintain the main advantages of conventional ECRIS such as high ionization degree and low ion energy. Reaching such high plasma density relies on the fact that the critical density grows with the microwave frequency squared. High microwave power provided the average electron energy on a level of 50-300 eV enough for efficient ionization even at neutral gas pressure range of 10 −4 -10 −3 mbar. Gasdynamic ECRIS has demonstrated a good performance producing high current (100-300 mA) multi-charged ion beams with moderate average charge (Z = 4-5 for argon). Gasdynamic ECRIS has appeared to be especially effective in low emittance hydrogen and deuterium beams formation. Proton beams with current up to 500 emA and RMS emittance below 0.07 π·mm·mrad have been demonstrated in recent experiments. C 2015 AIP Publishing LLC. [http://dx

One of the modern trends in the development of electron cyclotron resonance (ECR) sources of multicharged ions is enhancement of the power and frequency of microwave pumping. Therefore, gyrotrons-powerful sources of radiation in the millimetre wavelength range-are now used for the creation and heating of plasma. These generators of microwave radiation are capable of producing and confining plasma of very high density (10 13 cm −3 and higher), thus providing conditions for a substantial increase in the extracted ion beam current. Most ECR sources use for plasma confinement mirror magnetic traps with 'min B' configuration, which suppress MHD plasma instabilities. However, it is extremely difficult to construct such systems for pumping frequencies higher than 30 GHz because strong magnetic fields of complicated configuration are needed. All this makes the search for simpler axisymmetric MHD-stable systems for plasma confinement very topical.A cusp trap produced by two coils with opposite currents is the simplest MHD-stable magnetic trap. Magnetic lines at any point of plasma in such a trap have a curvature that suppresses MHD perturbation in the plasma. In the present work the possibility of creation of an effective ECR source of multicharged ions based on a cusp magnetic trap was investigated numerically and in experiments. The pioneer result is the realization of the quasi-gasdynamic regime of plasma confinement in the trap of the multicharged ion ECR source of multicharged ions with cusp configuration of the magnetic field. Experiments were made with a small cusp trap which was designed for plasma creation by 37.5 GHz gyrotron radiation under ECR conditions. The total current and ion charge state distribution in the extracted ion beam were studied. The results of experiments with the simplest kind of cusp trap have demonstrated good correspondence with theoretical calculations, and therefore the adequacy of the developed approach and the possibility to build more effective source on this basis. Two ways of possible evolution of ECR ion sources based on a cusp magnetic trap are proposed.

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