Penetration and screening of perpendicularly launched electromagnetic waves through bounded supercritical plasma confined in multicusp magnetic field
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India)
The question of electromagnetic wave penetration and screening by a bounded supercritical ({omega}{sub p}>{omega} with {omega}{sub p} and {omega} being the electron-plasma and wave frequencies, respectively) plasma confined in a minimum B multicusp field, for waves launched in the k perpendicular B{sub o} mode, is addressed through experiments and numerical simulations. The scale length of radial plasma nonuniformity (|n{sub e}/({partial_derivative}n{sub e}/{partial_derivative}r)|) and magnetostatic field (B{sub o}) inhomogeneity (|B{sub o}/({partial_derivative}B{sub o}/{partial_derivative}r)|) are much smaller than the free space ({lambda}{sub o}) and guided wavelengths ({lambda}{sub g}). Contrary to predictions of plane wave dispersion theory and the Clemow-Mullaly-Allis (CMA) diagram, for a bounded plasma a finite propagation occurs through the central plasma regions where {alpha}{sub p}{sup 2}={omega}{sub p}{sup 2}/{omega}{sup 2}{>=}1 and {beta}{sub c}{sup 2}={omega}{sub ce}{sup 2}/{omega}{sup 2}<<1({approx}10{sup -4}), with {omega}{sub ce} being the electron cyclotron frequency. Wave screening, as predicted by the plane wave model, does not remain valid due to phase mixing and superposition of reflected waves from the conducting boundary, leading to the formation of electromagnetic standing wave modes. The waves are found to satisfy a modified upper hybrid resonance (UHR) relation in the minimum B field and are damped at the local electron cyclotron resonance (ECR) location.
- OSTI ID:
- 21535139
- Journal Information:
- Physics of Plasmas, Vol. 18, Issue 2; Other Information: DOI: 10.1063/1.3551696; (c) 2011 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron Bernstein wave electron temperature profile diagnostic (invited)
Anisotropy induced wave birefringence in bounded supercritical plasma confined in a multicusp magnetic field