In overdense plasma for which the plasma frequency exceeds the cyclotron frequency, X-mode, nearperpendicular cyclotron emission does not propagate to the outboard plasma edge. However, under these conditions it remains possible for electron Bernstein waves (EBWs) to transmit emitted radiation from central plasma to the plasma exterior via a mode conversion to electromagnetic waves near the pla...

We present a characterization of molybdenum sources, ΓMo , core Mo content, NMo, and their dependencies on Alcator C-Mod operational regimes. The primary impurity source locations are the divertor, the inner wall and the ICRF antenna limiters. Boronization is used to coat the first-wall surfaces with a thin layer of B which greatly reduces the Mo sources for a period of time, eroding away with ...

A novel multiband multiple-input-multiple-output (MIMO) antenna system is proposed. The MIMO antenna system consists of two antenna elements, each of which comprises of three radiators: a driven monopole, an S-shaped strip and an inverted F-shaped strip and occupies footprint of 15x18.5x0.8 mm3 only. The driven monopole acts as a quarter-wave monopole and stimulate higher mode resonance. The tw...

A new multiple C-slotted microstrip patch antenna is proposed in the present study. A patch antenna is a wide-beam narrowband antenna. The microstrip patch antenna consists of a very thin metallic strip (patch) placed a small fraction of a wavelength above a ground plane. The patch can be designed in any possible shape and normally made of conducting materials such as copper or gold. This study...

We report a development and fabrication of an folded waveguide (FWG) antenna to produce and heat the plasma via ion Bernstein wave on the Large Helical Device (LHD) in the ion cyclotron range of frequency (ICRF). This antenna is 428 mm in height, 1050 mm in width and 3950 mm in length with 23 vanes and 24 folds. It will be installed to the horizontal vacuum port with an inclination angle of 38....

In Alcator C-Mod, we have investigated the compatibility of high power ion cyclotron range of frequencies antenna with high performance plasmas and all high-Z plasma facing components, to provide operational information for future devices such as ITER. Boronization appears to be critical achieving low radiated power plasmas and is eroded rapidly such that the best performance is lost when the i...

a new multiple c- slotted microstrip patch antenna is proposed.  a patch antenna is a wide-beam narrowband antenna. microstrip patch antenna consist of a very thin metallic strip (patch) placed a small fraction of a wavelength above a ground plane. the patch can be designed in any possible shape and normally made by conducting material copper or gold. this paper presents design of a c- slotted ...

Intense ion beam production is of high importance for various versatile applications from accelerator injectors to secondary mass spectrometry (SIMS). For these purposes, different types beams are needed and, accordingly, the optimum plasma produce desired beams. RF-type features a simple structure, density and low temperature, which essential negative production. A very compact source using pl...

Communication ‘blackout’ is a big challenge for modern space engineering. In the recent decade, the terahertz (THz) technology is believed to be an effective solution for the ‘blackout’ problem. Many research works about the transmission of THz waves in plasma slabs have been carried out. According to those works, the radio attenuation of THz waves in plasma slabs strongly depends on thickness ...

The results of the plasma start-up with ICRH U-2M RF discharges in H2+He mixture newly implemented controlled gas H2 concentration are presented. W7-X like antenna operated monopole phasing applied power ∼ 100 kW. We investigated pressure range p = 6×10−4 - 9 × 10−2 Pa. Plasma production an average density up to Ne 1013 cm−3 was observed at frequencies fundamental harmonic hydrogen cyclotron fr...