Total absorption of electromagnetic radiation in overdense plasma
- CAS Key Laboratory of Basic Plasma Physics and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)
The energy transformation from electromagnetic wave to plasmas polaritons in overdense plasma is investigated by using the theory of hydrodynamics in the thin cylinder limit and surface wave resonator. The grating experiment certifies the excitation of the surface wave. Through studying the role of the magnetic field in excitation of the surface wave and analyzing the frequency domain spectrum of the reflected wave, the time series of reflection, transmission and plasma density are diagnosed when the electromagnetic wave transforms into the surface wave. The experimental scheme of Bliokh [Phys. Rev. Lett. 95, 165003 (2005)] is improved. A steady overdense plasma in a cylindrical cavity is obtained by dc high voltage discharging and measurement is taken in series. The diffraction grating is fixed in optimum position after the distance from it to the chamber is adjusted. The reflection ratios of plasma and a piece of tinfoil are compared to avoid the effect of the standing wave. The effect of incident polarization is discussed and a measurement result is obtained with a 70 Gauss magnetic field. Further research on scanning measurement reveals that the collision rate is the only determinant element of the half absorption width. Numerical simulation is given, based on the theory of surface plasmons (SPs). The experimental data agree with the numerical simulation well near the resonance frequency f=5 GHz, while on the trailing edge, the curve is obviously expanded. The mechanism of these phenomena is very complex and other conceivable factors must exist during the excitation of SPs, which should be studied in the further research.
- OSTI ID:
- 20860146
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 13; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
COLLISIONS
CYLINDRICAL CONFIGURATION
DIFFRACTION GRATINGS
ELECTRIC POTENTIAL
ELECTROMAGNETIC RADIATION
EXCITATION
GHZ RANGE
HYDRODYNAMICS
MAGNETIC FIELDS
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA SIMULATION
PLASMONS
POLARIZATION
POLARONS
REFLECTION
RESONATORS
STANDING WAVES
SURFACES