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

We develop two approaches for coherent summation of Cherenkov superradiance (SR) pulses in order to obtain generation of electromagnetic fields of extremely high intensity. The first method is associated with correlating the phase of SR emission to the sharp edge of a current pulse, while the second approach is related to initiation of Cherenkov SR by an initial ultrashort seed rf pulse. In this paper we present the theoretical model describing both approaches alongside with results of experiments.

Methods of coherent summation of microwave superradiance pulses generated in independent channels

Significant progress in the development of terahertz radiation sources, in particular gyrotrons, marked the last decade. A number of radiation sources have been developed at IAP RAS, including CW gyrotrons, providing an output power level up to 1kW in the frequency range 0.26–0.52 THz and the gyrotrons with pulsed magnetic systems with 100kW power level at 0.7 THz and 1kW at 1THz frequency. The report provides an overview of the latest results obtained in IAP RAS related to applications of THz band gyrotrons.

Applications of THz band gyrotrons at IAP RAS: Current state and prospects

IAP RAS in cooperation with Gycom Ltd. prolongs manufacturing of gyrotron systems (RF power sources) for ITER under contract #17706413348180000850/45-320 of the 27.04.2018 with Russian DA “ITER Center”. Serial production had started after approval of Final design review in December 2016 following by approval of Manufacturing readiness review (MRR) in April 2017. MRR confirmed that Gycom has all necessary facilities for full cycle of gyrotron production: machining, brazing, assembling, exhausting and testing. Since that time two gyrotron systems were completed and successfully put through acceptance test meeting ITER specifications (see[1, 2]). Additional 1MW/170GHz/1000s gyrotron identical to serial one was produced by Gycom under request of F4E and shipped to Swiss Plasma Center facility in Lausanne after acceptance test carried out at Gycom with participation of F4E representatives in April 2017. Gyrotron system components will be located on 2 and 3 floors of ITER building B15 as schematically shows this picture.

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Status of the gyrotron complex for ITER: composition of the complex, manufacturing, obtained parameters, delivery conditions

The main results of the IAP RAS activity at the powerful pulse THz gyrotrons are presented. The power about 200 kW at the frequency of 0.67 THz in single impulses with durations of 30 microseconds has been reached. This gyrotron is successfully used to initiate localized (characteristic size in the order about 1 mm) discharge in gases. The models describing the dynamics of discharge initiated by THz radiation are under development. New experimental facility for long pulse or CW gyrotrons in frequency band 0.28-0.52 THz has been build based on helium-free 10 T cryomagnet.

G. G. Denisov

Papers

Methods of coherent summation of microwave superradiance pulses generated in independent channels

Applications of THz band gyrotrons at IAP RAS: Current state and prospects

Status of the gyrotron complex for ITER: composition of the complex, manufacturing, obtained parameters, delivery conditions

Generation of powerful THz radiation by electron beams and its interaction with plasma and gases

Frequency control in subterahertz gyrotrons