Physics of the Interaction Process in a Typical Coaxial Virtual Cathode Oscillator Based on Computer Modeling Using MAGIC

Chen, Xiao; Toh, Wee Kian; Lindsay, P. A.

doi:10.1109/tps.2004.827616

Cited by 18 publications

(8 citation statements)

References 12 publications

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“…It can be supposed that this disagreement stems from the fact that, in 1D models, transverse electron motions in a beam focused by a weak (but finite) magnetic field are ignored. In [27,28], attempts were made to theoretically study the processes in a beam with a VC by taking into account the finite strength of the magnetic field that focuses the beam electrons. However, the effect of the strength of the focusing magnetic field on the nonlinear unsteady processes that occur in an electron beam with an overcritical current has not yet been analyzed in detail.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the chaotic dynamics of an electron beam with a virtual cathode in an external magnetic field

Egorov

Hramov

2006

Plasma Phys. Rep.

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-The effect of the strength of the focusing magnetic field on chaotic dynamic processes occurring in an electron beam with a virtual cathode, as well as on the processes whereby the structures form in the beam and interact with each other, is studied by means of two-dimensional numerical simulations based on solving a self-consistent set of Vlasov-Maxwell equations. It is shown that, as the focusing magnetic field is decreased, the dynamics of an electron beam with a virtual cathode becomes more complicated due to the formation and interaction of spatiotemporal longitudinal and transverse structures in the interaction region of a vircator. The optimum efficiency of the interaction of an electron beam with the electromagnetic field of the vircator is achieved at a comparatively weak external magnetic field and is determined by the fundamentally two-dimensional nature of the motion of the beam electrons near the virtual cathode.

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Section: Introductionmentioning

confidence: 99%

Investigation of the chaotic dynamics of an electron beam with a virtual cathode in an external magnetic field

Egorov

Hramov

2006

Plasma Phys. Rep.

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“…Therefore, can be derived from (6). Assuming that the relativistic plasma frequency is a constant in the space (or slowly varying in time), and considering as a scalar, the solution of (1) is (7) with (8) Using (2), (3), (8), and adopting the Coulomb criterion, i.e., , we can obtain the electron momentum equation (9) Equation (9) can be solved in 2-D cylindrical coordinates, in which the angular component is ignored. Expanding (9) leads to the two independent equations related to and components (10)…”

Section: Steady-state Relativistic-fluid-maxwell Equationsmentioning

confidence: 99%

“…The peak-to-peak microwave power efficiency over 5% has been achieved in some experiment for the coaxial vircator [4]. Prior to deliberate experiments, computer simulation have been chosen for the study and understanding of coaxial vircators, and consistent results have been obtained between the experiments and the simulation codes, such as KARAT [7] and MAGIC [8].…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional theoretical analysis of the dominant frequency in the inward-emitting coaxial vircator

Xing

Wang

Huang

et al. 2006

IEEE Trans. Plasma Sci.

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Two-dimensional steady-state analysis for the electron flow in an inward-emitting coaxial virtual cathode oscillator is presented. Based on the relativistic-fluid-Maxwell equations, the relativistic plasma frequency characteristics and its dependence on the geometric parameters are derived. The resulting plasma frequency solution scales linearly with the diode current. The exact dominant frequency is solved numerically, which gives the theoretical support for the simulation result that the microwave frequency in a coaxial vircator is similar to that produced by a planar vircator with the same small anode-cathode gap distance. Numerical result shows that higher frequency can be achieved in the coaxial vircator for higher applied voltage and smaller anode-cathode gap distance. The numerical solutions of the dominant frequencies predict the measured and simulated values within 10%.Index Terms-Coaxial virtual cathode oscillator, high-power microwave sources, relativistic-fluid-Maxwell equations, relativistic plasma frequency.

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“…A coaxial vircator is a modified version of the vircator to improve its low efficiencies [17]. Most coaxial vircators are designed to install the cathode outside the cylindrical anode and emit electrons in an inner radial direction [17][18][19][20][21][22][23][24][25][26][27][28]. The brief summarizations on the performances of other works are shown in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Operation Features of a Coaxial Virtual Cathode Oscillator Emitting Electrons in the Outer Radial Direction

et al. 2021

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The operation features of the coaxial virtual cathode oscillator emitting electrons in the outer radial direction were investigated through simulations and experiments. A coaxial vircator was compared with an axial vircator when the anode to cathode distance of both vircators was 6 mm. The proposed coaxial vircator was operated when the anode to cathode distance was 5 mm, 6 mm, and 7 mm. The peak power and frequency of the microwave generated from the proposed coaxial vircator when the anode to cathode distance was 6 mm were 20.18 MW and 6.17 GHz, respectively. The simulations and experiments show that the proposed coaxial vircator generates 80% more microwave power than the axial vircator with the same anode to cathode distance. According to the simulations and experiments, the proposed coaxial vircator tends to generate a higher power average when the anode to cathode distance was larger than 5 mm. The frequency of the proposed coaxial vircator when the anode to cathode distance was 5 mm and 7 mm was approximately 8 GHz and 5 GHz, respectively. The geometric factor of the proposed coaxial vircator was considered to be the reason for the greater microwave power generation than the axial vircator. The frequency of the proposed coaxial vircator decreases inversely proportional with the anode to cathode distance as observed in the axial and basic coaxial vircators.

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Physics of the Interaction Process in a Typical Coaxial Virtual Cathode Oscillator Based on Computer Modeling Using MAGIC

Cited by 18 publications

References 12 publications

Investigation of the chaotic dynamics of an electron beam with a virtual cathode in an external magnetic field

Investigation of the chaotic dynamics of an electron beam with a virtual cathode in an external magnetic field

Two-dimensional theoretical analysis of the dominant frequency in the inward-emitting coaxial vircator

Operation Features of a Coaxial Virtual Cathode Oscillator Emitting Electrons in the Outer Radial Direction

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