Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Recent research and development has been incredibly successful at advancing the capabilities for vacuum electronic device (VED) sources of powerful terahertz (THz) and near-THz coherent radiation, both CW or average and pulsed. Currently, the VED source portfolio covers over 12 orders of magnitude in power (mW-to-GW) and two orders of magnitude in frequency (from ; 10 THz). Further advances are still possible and anticipated. They will be enabled by improved understanding of fundamental beam-wave interactions, electromagnetic mode competition and mode control, along with research and development of new materials, fabrication methods, cathodes, electron beam alignment and focusing, magnet technologies, THz metrology and advanced, broadband output radiation coupling techniques.

Vacuum Electronic High Power Terahertz Sources

The electron cyclotron maser (ECM) is based on a stimulated cyclotron emission process involving energetic electrons in gyrational motion. It constitutes a cornerstone of relativistic electronics, a discipline that has emerged from our understanding and utilization of relativistic effects for the generation of coherent radiation from free electrons. Over a span of four decades, the ECM has undergone a remarkably successful evolution from basic research to device implementation while continuously being enriched by new physical insights. By delivering unprecedented power levels, ECM-based devices have occupied a unique position in the millimeter and submillimeter regions of the electromagnetic spectrum, and find use in numerous applications such as fusion plasma heating, advanced radars, industrial processing, materials characterization, particle acceleration, and tracking of space objects. This article presents a comprehensive review of the fundamental principles of the ECM and their embodiment in practical devices.

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The electron cyclotron maser

This article reviews the state-of-the-art in high-power microwave source research. It begins with a discussion of the concepts involved in coherent microwave generation. The main varieties of microwave tubes are classified into three groups, according to the fundamental radiation mechanism involved: Cherenkov, transition, or bremsstrahlung radiation. This is followed by a brief discussion of some of the technical fundamentals of high-power microwave sources, including power supplies and electron guns. Finally, the history and recent developments of both high-peak power and high-average power sources are reviewed in the context of four main areas of application: (1) plasma resonance heating and current drive; (2) rf acceleration of charged particles; (3) radar and communications systems; and (4) high-peak power sources for weapons-effect simulation and exploratory development.

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Review of high-power microwave source research

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Plasma Physics and Controlled Fusion Conference: Focussing on Tokamak Research

Electronic efficiency of 26%, close to the value calculated for a perfect electron beam in a type of FEM based on the stimulated electron cyclotron radiation, has been obtained for the first time.

High-efficiency CARM

A new method for increasing the angular range of a waveguide antenna for remote steering of the wave-beam direction in thermonuclear-fusion experimental setups with plasma magnetic confinement is proposed. Characteristics for large beam inclination angles can be improved using the synthesized nonuniform waveguide profile. For small angles, the characteristics remain invariable, the waveguide profile differs only slightly from the regular shape, and can be fit to limited waveguide-channel sizes.

A Waveguide Antenna with an Extended Angular Range for Remote Steering of Wave-Beam Direction

An Overview of the Iter EC Transmission Line

A follow-up of the FOM fusion FEM for 1 MW, 1 s

We study non-stationary problems of penetration into and reflection from a semiconductor plate of powerful microwave radiation. The plate is a base of the fast switch, which is activated by a laser-driven photoconductivity and is heated by the commutated microwave power. Analytical criteria for stationary solutions are given for activated (quasi-metallic plate) and deactivated (low-loss dielectric plate) states of the switch under the conditions of powerful microwave heating and external cooling. Results of numerical simulations are provided also for problems of the switch activation by a microwave heating initiated by a short-pulsed laser radiation, which rapidly increases the carrier density. Numerical simulations are carried out by means of the FDTD method with the UPML absorbing boundary conditions. Examples show the system behavior depending on the basic parameters of the problem - microwave field intensity, laser pulse energy and semiconductor doping density.

G. G. Denisov

Papers

High-efficiency CARM

A Waveguide Antenna with an Extended Angular Range for Remote Steering of Wave-Beam Direction

An Overview of the Iter EC Transmission Line

A follow-up of the FOM fusion FEM for 1 MW, 1 s

Modeling of dynamic effects in a laser-driven semiconductor switch of powerful microwave radiation