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

The study of the gas discharge in quasioptical beams of electromagnetic radiation of the terahertz (THz) frequency band is attractive for fundamental and applied research. The study of this discharge was made possible by the emergence of unique and reliable sources of radiation of the THz frequency band. Electrovacuum radiation sources of THz band (gyrotrons) have been created at the Institute of Applied Physics (IAP RAS) (Nizhny Novgorod) with a power order of 100 kW in pulsed mode of operation (pulse duration ~ several dozens of µs) and a kilowatt in continuous mode, and investigations of gas discharge phenomena in various gases have been started. Even the first experimental studies of the discharge in noble gases (argon) showed a significant difference in the THz discharge from the discharge at lower frequencies, even in the dynamics of discharge glow. The maximum of the discharge glow was observed after the end of the THz pulse and the afterglow duration was hundreds of microseconds. This paper is devoted to the theoretical and experimental study of the breakdown thresholds of various gases by radiation at 263 and 670 GHz and the study of discharge dynamics in noble and molecular gases under the action of 670 GHz radiation.

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