Microwave-plasma in a simple magnetized torus

Journal Article · Thu May 01 00:00:00 EDT 1997 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872320· OSTI ID:580686

Rypdal, K; Fredriksen, M; Olsen, O M ^[1]; Hellblom, K G ^[2]

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1. Institute of Mathematical and Physical Sciences, University of Tromso/, 9037 Tromso/ (Norway)
2. Alfven Laboratory, Royal Institute of Technology, S-10044 Stockholm (Sweden)

In a magnetized torus with no poloidal field component, a weakly ionized plasma is produced by microwaves at 2.45 GHz in the O-mode as well as the X-mode. The neutral gas pressure p{sub g} ranges from 5{times}10{sup {minus}5} to 1{times}10{sup {minus}3} mbar, n{sub e}{approximately}1{minus}5{times}10{sup 16}m{sup {minus}3}, and T{sub e}{approximately}2{minus}6 eV. The O-mode is only weakly absorbed at the electron cyclotron resonance (ECR), but is partly converted to the X-mode by wall reflections. The X-mode is absorbed via the upper hybrid resonance (UHR), presumably through conversion to and absorption of electron Bernstein waves (EBW). For p{sub g}{gt}1{times}10{sup {minus}3} mbar the EBW absorption is collisional, but for lower p{sub g} a collisionless transit particle mechanism could be responsible. Typically the spatial plasma distribution depends mainly on the major radius R, and the measured n{sub e}(R) increases monotonically with R from the ECR to an UHR near the outer wall. T{sub e} is determined by the particle balance, and is proportional to the ionization energy. The average n{sub e} is determined by power balance, and increases with wave power. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 580686
• Journal Information: Physics of Plasmas, Vol. 4, Issue 5; Other Information: PBD: May 1997
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION
PLASMA PRODUCTION
ECR HEATING
MICROWAVE RADIATION
TOROIDAL CONFIGURATION
MAGNETIC FIELDS
INHOMOGENEOUS PLASMA
PLASMA RADIAL PROFILES
PLASMA POTENTIAL
PLASMA DIAGNOSTICS
ELECTRON DENSITY
ELECTRON TEMPERATURE
ELECTRON PLASMA WAVES
WAVE PROPAGATION
ABSORPTION
HYDROGEN
ARGON
HELIUM
MAGNETIC CONFINEMENT
BERNSTEIN MODE