Design of an Optimized Resonant Cavity for a Compact Sub-Terahertz Gyrotron

Sabchevski

2012

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Powerful sources of coherent radiation in the sub-terahertz and in the terahertz frequency range of the electromagnetic spectrum are necessary for a great and continuously expanding number of applications in the physical research and in various advanced technological processes as well as in radars, communication systems, for remote sensing and inspection etc.. In recent years, a spectacular progress in the development of various gyrodevices and in particular of the powerful high frequency (sub-terahertz and terahertz) gyrotron oscillators has demonstrated a remarkable potential for bridging the so-called terahertz power gap and stimulated many novel and prospective applications. In this review paper we outline two series of such devices, namely the Gyrotron FU Series which includes pulsed gyrotrons and Gyrotron FU CW Series which consist of tubes operated in a CW (continuous wave) or long pulse mode, both developed at the FIR FU Center. We present the most remarkable achievements of these devices and illustrate their applications by some characteristic examples. An outlook for the further extension of the Gyrotron FU CW Series is also provided.

Section: Discussionmentioning

confidence: 99%

Section: Recently Developed Gyrotrons Members Of the Fu Cw C And Fu mentioning

confidence: 99%

Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range

Sabchevski

2012

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“…In this section we consider an inhomogeneous Helmholtz equation (25) where the right−hand term ) , ( z E ω represents the excitation of the cavity. It is supplemented with the same boundary conditions as in Sec.2.…”

Section: Solution Of the Boundary Value Problem For The Inhomogeneous...mentioning

confidence: 99%

“…This concept has been explored and applied to the CAD of several gyrotrons for spectroscopic applications [22,24]. Additionally, in [25] it has been demonstrated that a promising opportunity for widening of the tunability band is the usage of resonators in which the regular part of the cavity is replaced by a slightly up−tapered section [26]. It should be mentioned also that in most of the cases, the interaction which takes place in the cavity is the one between the electron beam and the backward−wave components of the HOAM (TE m,n,-q ), i.e.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on Finite-Bandwidth Resonances of High-Order Axial Modes (HOAM) in a Gyrotron Cavity

Sabchevski

2015

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Many novel and prospective applications of the gyrotrons as sources of coherent radiation require a broadband and continuous frequency tunability. A promising and experimentally proven technique for the latter is based on a successive excitation of a sequence of high-order axial modes (HOAM) in the cavity resonator. Therefore, the studies on HOAM are of both theoretical and practical importance. In this paper we present and discuss the methods and the results of a numerical investigation on the resonances of HOAM in a typical open gyrotron cavity. The simulations have been performed using the existing as well as novel computational modules of the problem oriented software package GYROSIM for solution of both the homogeneous and the inhomogeneous Helmholtz equation with radiation boundary conditions, which governs the field amplitude along the axis of the resonant structure. The frequency response of the cavity is studied by analyzing several resonance curves (spectral domain analysis) obtained from the numerical solution of the boundary value problem for the inhomogeneous Helmholtz equation by the finite difference method (FDM). The approach proposed here allows finite-bandwidth resonances of HOAM to be identified and represented on the dispersion diagram of the cavity mode as bands rather than as discrete points in contrast to the frequently used physical models that neglect the finite width of these resonances. Developed numerical procedures for calculation of the field profiles for an arbitrary frequency and excitation will be embedded in the cold−cavity and self-consistent codes of the GYROSIM package in order to study the beam−wave interaction and energy transfer in gyrotron cavities.

“…We propose to use an uptapered cavity which is known to have several benefits [7,8]. The middle section of this cavity is twice as long (L 0 2 ¼ 30mm) as of the existing cavity (L 2 = 15 mm).…”

Section: Uptapered Cavitymentioning

confidence: 99%

Frequency Tunable Gyrotron FU CW VA for Measuring Hyperfine Split of Positronium

Dumbrājs

2010

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