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 70Gauss 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=5GHz, 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.
A simulation model, based on the linear tip model of Rosenbluth, Berk and Van Dam (RBV), is developed to study frequency sweeping of toroidal Alfvén eigenmodes (TAEs). The time response of the background wave in the RBV model is given by a Volterra integral equation. This model captures the properties of TAE waves both in the gap and in the continuum. The simulation shows that phase space structures form spontaneously at frequencies close to the linearly predicted frequency, due to resonant particle-wave interactions and background dissipation. The frequency sweeping signals are found to chirp towards the upper and lower continua. However, the chirping signals penetrate only the lower continuum, whereupon the frequency chirps and mode amplitude increases in synchronism to produce an explosive solution. An adiabatic theory describing the evolution of a chirping signal is developed which replicates the chirping dynamics of the simulation in the lower continuum. This theory predicts that a decaying chirping signal will terminate at the upper continuum though in the numerical simulation the hole disintegrates before the upper continuum is reached.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.