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The cell-type continuous electromagnetic radiation system is a demonstration device capable of generating high-power millimeter electromagnetic waves of a specific wavelength and observing their effects on living organisms. It irradiates a biological sample placed in a 30 x 30 x 50 cm³ cell with electromagnetic waves in the 3.15-mm-wavelength region (with an output of ≥1 W) and analyzes the temperature change of the sample. A vacuum electronic device-based coupled-cavity backward-wave oscillator converts the electron energy of the electron beam into radiofrequency (RF) energy and radiates it to the target through an antenna, increasing the temperature through the absorption of RF energy in the skin. The system causes pain and ultimately reduces combat power. A cell-type continuous electromagnetic radiation system consisting of four parts--an electromagnetic-wave generator, a high-voltage power supply, a test cell, and a system controller--generates an RF signal of ≥1 W in a continuous waveform at a 95-GHz center frequency, as well as a chemical solution with a dielectric constant similar to that of the skin of a living organism. An increase of 5 °C lasting approximately 10 s was confirmed through an experiment. [ABSTRACT FROM AUTHOR]

The analysis of the multimode behavior of the interaction cavity for 42-GHz gyrotron is presented here. The in-house developed codes single-mode cold cavity solver (SMCCS) and GYCAD and commercial particle-in-cell (PIC) simulator MAGIC are used in the design and analysis of 42-GHz gyrotron cavity. SMCCS is used for the calculation of cold cavity parameters such as $Q$ factor, resonant frequency, and the axial electric field profile, which are further used in the beam–wave interaction computation. The PIC code is used here for the parametric optimization and time-dependent-multimode beam–wave interaction simulations of the interaction cavity. The mode purity in terms of the electromagnetic power in individual modes is also calculated using the data generated in the beam–wave interaction simulations. The single-mode analysis of the cavity is also performed using the analytical code GYCAD based on the generalized nonlinear theory. The results obtained by the PIC simulator and GYCAD are discussed and compared here. The analysis of the electron beam misalignment, which may occur due to the radial shifting or tilting of the different components during the fabrication of the device, is also performed and the effects on the efficiency, mode competition, and mode stability are discussed in detail. [ABSTRACT FROM AUTHOR]

This article presents the effect of significant up-tapering of the resonator midsection on diffractive quality factor, resonant frequency, axial field profile shift, and axial separation between peaks of higher order axial modes (HOAMs) in a gyrotron resonator. Significant up-tapering of the resonator midsection causes the quality factor curves of HOAMs to come close to each other and eventually crossover. This allows HOAMs to have comparable or even higher quality factor value than the lower axial modes—a situation which is not possible in a conventional resonator. Due to this, the operating current for all axial modes can keep an order of magnitude. The up-tapering also shifts the axial field profile toward the output section of the resonator and leads to the loss of spatial symmetry that exists in the axial separation between the peaks of HOAMs in a conventional resonator. Computations have been performed for 0.2-, 0.5-, and 1-THz resonator using single-mode cold cavity solver code developed at CSIR-CEERI. Numerical validation with published results, for 0.2- and 0.5-THz conventional resonators, has also been carried out. [ABSTRACT FROM AUTHOR]

A 42-GHz, 200-kW gyrotron was developed and tested for the Indian plasma fusion system. The gyrotron was designed for the TE0,3 operating mode. The configuration of the triode-type magnetron injection gun (MIG) with the linear RF output, undepressed collector, and face-cooled double disk window was adopted in this gyrotron because of the first development experience. The complete tube was developed and processed at Central Electronics Engineering Research Institute (CEERI), Pilani, India. The RF testing of the gyrotron was performed at the participating institute, Institute of Plasma Research (IPR), Gandhinagar, India. Due to some cooling issues in the collector region, the tube was tested by a resistive capacitor network-based power supply for a very short pulse in place of a long pulse, high voltage power supply. The tube was tested up to the beam voltage of 51 kV and a beam current of 12 A at the cavity magnetic field of 1.61 T for the short pulse of $500~\mu \text{s}$. The tube was inserted into the magnet system consisting of a main electromagnet, auxiliary gun coils, and collector magnets. The multi-hole and single hole couplers were used to measure the RF power in the TE0,3 mode and the overall power, respectively. The measured results were also compared with the simulated results and a close agreement of the results was found. The short pulse testing confirms the electrical design and the development approach for the 42-GHz gyrotron tube. [ABSTRACT FROM AUTHOR]

Inverse magnetron injection gun (IMIG) provides several advantages over simple MIG especially in high-power, high-frequency gyrotron. Sub-millimeter (>230 GHz), high-power (≥1 MW) gyrotrons would be required in futuristic plasma fusion machines to fulfill the need of tens of megawatt RF power for electron cyclotron resonance heating. Here, in this paper, an IMIG is designed for 0.24-THz, 1-MW gyrotron. First, the tradeoff design equations and technical constraints are used to synthesize the electrodes geometry and electrical parameters of IMIG. This synthesized IMIG model is further simulated to finalize the design using electron trajectory code EGUN. Simultaneously, the magnet system including the auxiliary gun coils and superconducting magnets (SCM) is also designed and the obtained magnetic field profile is used in the IMIG simulations. In the case of high-power MIG, the suppression of the beam halo is a major design concern and analyzed critically in the present IMIG design. The shape of the modulating anode and main anode is optimized to make a beam halo shielding. This IMIG is designed for a very high-order mode (TE46,17) simple cylindrical cavity, which confines the range of the tolerance in the electron beam parameters. So, a detailed parametric and misalignment analysis is also performed with respect to the electron beam parameters, such as pitch factor, velocity spread, and guiding center radius spread. These parametric and misalignment analyses would be utter helpful in the fabrication, assembling and testing of the IMIG as well as gyrotron. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach for computation of high-order axial modes (HOAMs) in a conventional and uptapered gyrotron resonator. A code has been developed which computes the eigenfrequency, Q-factor and axial field profile of HOAMs in the absence of electron beam in the resonator. Cyclic coordinate search method has been used for the optimization of complex eigenfrequencies, which obviates the computation of gradients of radiation boundary conditions and, hence, reduces computational complexity. HOAMs have been computed for resonators operating at 10, 132, 203, and 424 GHz, and the results obtained have been found to be in good quantitative agreement with the experimental and numerical data available in the published literature. Broadband continuous frequency tuning bandwidth found for subterahertz resonators also agrees well with the published results. HOAMs computed for 1-THz gyrotron resonator designed at CSIR-CEERI have also been presented. [ABSTRACT FROM AUTHOR]

Multimegawatt RF power in millimeter waveband (30–300 GHz) is required in the magnetically confined plasma fusion reactors. In this paper, the design of 170-GHz, 2-MW gyrotron with coaxial-cavity configuration is discussed. The mode selection and optimization of corrugation geometry of the coaxial insert are performed and discussed in detail. The beam-wave interaction computation and interaction cavity design are carried out using a particle-in-cell code. The beam-wave interaction analysis confirms 2.2-MW RF power at the 170.07-GHz frequency with more than 40% interaction efficiency. A 5.5-MW coaxial magnetron injection gun (C-MIG) is designed to launch the gyrating electron beam at the first radial maxima of the electric field peak of the selected operating mode in the interaction cavity. The magnetic system consisting of auxiliary coils and superconducting coils is also designed as per the requirement in MIG design. [ABSTRACT FROM AUTHOR]

The authors would like to make a correction to the affiliation section of on page 1, because one of the affiliations in was missing. The correct affiliation section of should read as follows. [ABSTRACT FROM AUTHOR]

Herein, we have presented a weak acid-promoted tandem aza-Michael-aldol strategy for the synthesis of diversely fused pyrrolo[1,2- a ]quinoline (tricyclic to pentacyclic scaffolds) by the construction of both pyrrole and quinoline ring in one pot. The described protocol fabricated two C-N bonds and one C-C bond in the pyrrole-quinoline rings which have been sequentially formed under transition-metal-free conditions by the extrusion of eco-friendly water molecules. A ketorolac drug analogue has been synthesized following the current protocol, and one of the synthesized tricyclic pyrrolo[1,2- a ]quinoline fluorophores has been used to detect highly toxic picric acid via the fluorescence quenching effect.