Strong scattering of high-power millimeter waves at 140 GHz has been shown to take place in heating and current-drive experiments at TEXTOR when a tearing mode is present in the plasma. The scattering signal is at present supposed to be generated by the parametric decay instability. Here we describe the heterodyne detection system used to characterize the newly discovered signal measured at TEX...

Results of energy and frequency measurements on the Twente Raman FEL are presented and discussed. A highest energy of 230 mJ was measured using a joule meter. The spectrum was determined using waveguide cutoff filters. These measurements generally showed a broad spectrum containing two or more peaks. Far from magneto-resonance this indicates that the radiation field grows at the upper as well a...

Laboratory observations of enhanced loss of fast electrons trapped in a magnetic mirror geometry irradiated by shear Alfvén waves (SAW) are reported. A population of runaway electrons generated by second harmonic electron-cyclotron-resonance heating, as evidenced by the production of hard x rays with energy up to 3 MeV, is subjected to SAW launched with a rotating magnetic field antenna. It is ...

The uniformity of plasma generation in electron cyclotron resonance (ECR) reactors for materials processing, and the subsequent uniformity of fluxes to the substrate, are generally a function of the mode of the microwave radiation injected into the chamber. In this paper, a finite difference time domain (FDTD) simulation is used to demonstrate the consequences of exciting an ECR reactor using a...

A thin, annular plasma sheet in a waveguide slows down the phase velocity of electromagnetic modes in a plasma density window for frequencies below the electron cyclotron frequency via cerenkov interaction. At lower densities, the plasma is not effective enough to reduce the phase velocity of the em waves below c. At higher densities the plasma expels the radiation field leading to enhancement ...

Blackbody levels of emission in the electron cyclotron range of frequencies have been observed from an overdense (vpe;3vce) Madison Symmetric Torus @Dexter et al., Fusion Technol. 19, 131 ~1991!# reversed field pinch plasma, a result of electrostatic electron Bernstein waves emitted from the core and mode converted into electromagnetic waves at the extreme plasma edge. Comparison of the measure...

We present a model for generation mechanisms of the optical pulsations recently detected from the Geminga pulsar. We argue that this is just a synchrotron radiation emitted along open magnetic field lines at altitudes of a few light cylinder radii (which requires that Geminga is an almost aligned rotator), where charged particles acquire non-zero pitch-angles as a result of the cyclotron absorp...

Amaximum entropy approach has been applied to the tomographic inversion of the line integrated measurements of radiation power ux by a multichannel bolometer system. This method was applied to a H-mode discharge in the W7-AS stellarator, with increasing radiation from the plasma core after the transition being observed. Also a neutral beam injection discharge was investigated, and the time evol...

In this paper we discuss the behaviour of the longitudinal modes of a magnetized non collisional plasma subjected to an external electromagnetic field. We apply a semiclassical formalism, with the electrons being studied in a quantum mechanical viewpoint whereas the electromagnetic field in the classical context. We calculate the dielectric function in order to obtains the modes and found that,...