The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Terahertz (THz) light helicity sensitive photoresponse in GaAs/AlGaAs high electron mobility transistors and silicon metal oxide semiconductor field effect transistors is reported. The helicity dependent detection mechanism is interpreted as an interference of plasma oscillations in the channel of the field-effect-transistors (generalized Dyakonov-Shur model). The observed helicity dependent photoresponse...
Latest results from a second harmonic gyro-TWA experiment at Strathclyde University are presented. The Ka-band experiment uses a helically corrugated waveguide. Simulations have been performed to predict the amplifier gain and bandwidth. The simulations are compared to laboratory measurements of the cold waveguide dispersion using a new, improved design of polarization converter.
Seven gyrotrons are currently in operation in the ASDEX Upgrade Electron Cyclotron Resonance Heating (ECRH) system delivering a total of 3.9 MW to the plasma at 140 GHz. The 3 new gyrotrons are capable of 2-frequency operation and may heat the plasma alternatively with 2.1 MW at 105 GHz.
A complex cavity with gradual transition is employed in the 94 GHz gyrotron. A self-consistent field nonlinear theory has been used and numerical simulations for electron beam interaction with RF modes are given. A pulse output power of 235.2 kW is obtained by simulation at a beam voltage of 60 kV with beam current of 10 A, a velocity ratio of 1.45, and magnetic field 17kG, corresponding to an efficiency...
We have demonstrated an order of magnitude increase in terahertz (THz) power by creating an asymmetric plasma filament whose density decreases gradually in its tail. Comparison between models with and without accounting for amplification indicates amplification of the THz wave in the plasma.
The Brewster window is a broadband window solution for H&CD applications. Its geometry is quite complex and involves brazing of diamond and copper, which have very different thermal expansion coefficients. In this paper, a study of its feasibility was carried out by FEM structural analyses.
Simulations have been conducted at the University of Strathclyde to study the electrodynamics of the cyclotron maser instability responsible for generating auroral magnetospheric radio emission from stars and planets with a dipole like magnetic field configuration.
The multi-frequency gyrotron are under development in JAEA. Oscillations at 170 GHz, 137 GHz and 104 GHz are demonstrated with the Gaussain beam output. At present, 0.9 MW/70 sec, 1.1 MW/5 sec were obtained at 170 GHz. In parallel, a fast frequency control was demonstrated between 170 GHz and 167 GHz using a super-conducting sweeping coil.
We use fibre-drawing methods to make large quantities of indium wire arrays embedded in polymer. By controlling the size and spacing of the wires in the arrays, we fabricate electric metamaterials with plasma frequencies in the THz through to the mid-IR. We also discuss the limitations of this process using the current choice of materials.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.