29th Symposium on Fusion Technology (SOFT 2016)

P1.018 Properties of plasma injected in open magnetic trap from independent UHF source

5 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 18

Poster A. Experimental Fusion Devices and Supporting Facilities P1 Poster session

Speaker

Sulkhan Nanobashvili (Andronikashvili Institute of Physics)

Description

Various ways of filling the open magnetic trap with plasma are used in different experiments on study of plasma in order to develop methods of plasma heating and confinement, to study the interaction of electromagnetic waves with magnetoactive plasma etc. Among all existing methods the ultra high frequency (UHF) contactless methods are used frequently. We have proposed the method of filling the open magnetic trap (with a homogeneous and mirror configuration of magnetic field) by plasma injection along the magnetic field from the independent stationary UHF source separated from the trap. In this paper stationary UHF plasma source, its characteristics and possibility of filling open magnetic trap with plasma injected from the source are investigated. Plasma is created in the UHF source at the frequency 2400 MHz (150W) in the electron cyclotron resonance (ECR) regime under working gas pressure 10^-5-5÷10^-2-2 Torr. By changing discharge conditions one can modify the injected plasma density from 10⁸8 to 10¹²12 cm^-3-3 , at the temperature Te = 2÷3 eV. The possibility of efficient plasma injection from the source into the open magnetic trap with uniform field is shown experimentally. Properties of plasma in the trap are presented under various experimental conditions. It turned out that plasma lifetime in the trap is determined by classical mechanism of particle escape at the expence of collisions. At fixed value of magnetic field in the trap plasma lifetime practically does not change with variation of neutral gas pressure and reaches the value 4x10^-3-3 s at magnetic field strength in the trap equal to 1600 Oe. A set of experimental data gives the possibility to conclude that such method of filling the open magnetic trap with plasma can be successfully used in various physical experiments.