Speaker
Dr
Vadim Skalyga
(Institute of Applied Physics of Russian Academy of Sciencies)
Description
During recent research in the IAP RAS a new type of ECR ion sources with plasma heating by powerful gyrotron millimeter wave radiation was developed. Due to the high frequency and power of heating microwaves plasma with unique parameters (density of about 10$^{13}$ cm$^{-3}$, the electron temperature of 100 eV and a temperature of the order of 1 eV ions) could be created in a magnetic trap of the ion source. Under such conditions a so-called quasi-gasdynamic plasma confinement regime, characterized by a short lifetime (about 10 microseconds), is realized in the source trap. Such short lifetime in combination with high plasma density allows to create ion beams of light or heavy multiply charged ions with current density up to 800 mA/cm$^2$. The possibility of such hydrogen and deuterium ion beams formation has been demonstrated at pulsed experimental facility SMIS 37 in case of plasma heating with gyrotron microwave radiation at frequency of 37.5 GHz and a power of 100 kW and using of a simple mirror magnetic trap created by a pair of pulsed solenoids. Further research on the development of high current ECR ion sources demands higher pulse repetition rate or transition to a CW regime of the ion beam generation. In this case, the use of pulsed magnetic systems becomes impossible. In this paper we propose a design of a magnetic trap with mirror field configuration produced with permanent magnets for plasma confinement in the ion source of the type described. The magnetic field of the trap at its mirrors is 1.5 T, i.e. it allows to realize ECR plasma heating by radiation with frequencies up to 45 GHz. The use of a permanent magnet trap has a number of significant advantages over a "warm" or superconducting coils: it allows to operate both in pulsed and continuous mode; it eliminates the need for high-voltage insulation of solenoids from the discharge chamber placed under high potential; it does not require constant cooling; it doesn’t require power supply and consequently it has a compact size and provides higher reliability of the entire device. Another extremely important advantage of the permanent magnet trap is configuration of magnetic field lines more resistant to the MHD perturbations compared to a simple mirror trap.
Primary author
Dr
Vadim Skalyga
(Institute of Applied Physics of Russian Academy of Sciencies)
Co-authors
Dr
Alexander Voitovich
(Institute of Applied Physics of Russian Academy of Sciencies)
Dr
Evgeniy Mironov
(Institute of Applied Physics of Russian Academy of Sciencies)
Mr
Ivan Izotov
(Institute of Applied Physics of Russian Academy of Sciencies)
Dr
Oleg Palashov
(Institute of Applied Physics of Russian Academy of Sciencies)
