__Keywords:__orotron millimeter and submillimeter range two-row periodic structure first space harmonic 2nd space harmonic plane electron beam multi-focal focusing mirror

Ye. A Myasin, A.N. Solovyov

The purpose of this work is the study of the possibility of an increase in the power of the generatable oscillations of the short-wave part of the millimeter and submillimeter range in orotron with the two-row periodic structure (TRPS), and it is more concrete specific - in orotron with TRPS with the wavelength of 1mm, operating voltage of ≤ 6 kV and operating current 3A. Since for the work of such a orotron on the first space harmonic TRPS to create problematically (period TRPS of ≤ of 0,15mm, the height of rows of 0.2 mm, and filling of period 0,5), then the possibility of an increase in the power is investigated for orotron, which works on the 2nd space harmonic. In this case the period TRPS of ≤ of 0,3mm and 0,25 mm, the height of rows of 0.2 mm, and filling of period 0,25. It is known that in orotron the power of the generatable oscillations can be increased, increasing the width of strip electronic beam. In classical orotron with the spherical focusing mirror of the hemispherical open resonator (OR), which has the Gaussian distribution of HF field over the transverse and longitudinal coordinate of interaction space, to make this is possible due to an increase in the radius of sphere. This is not desirable for many reasons. Task can be sufficient simply solved by the replacement of the spherical mirror by cylindrical, the generative of cylinder of which is perpendicular to the motion of electronic beam. For this there can be spherocylindrical focusing the mirror used, which is the section of the cylinder, which passes into the sphere at both ends. That not to exchange, the Gaussian distribution of HF field in this OR will be in the direction of the motion of electronic beam, t.e. along the interaction space limits its length. In connection with the fact that with the shortening of wavelength in the short-wave part of the millimeter and submillimeter range grow ohmic losses in OR, it was necessary to investigate their influence on the energy parameters of orotron and to if necessary find the possibility of an increase in the length of interaction with the retention of properties this OR. In the work on the basis of the nonlinear theory of discrete interaction is carried out the optimization of the parameters of orotron from TRPS, which works on the 2nd space harmonic at the wavelength of 1mm with the stress of up to 6kV for four values of magnitude of losses δ, which are differed from each other as the 1:2: 4: 8. It is given calculation procedure based on the example of the case with δ = 4. The given results of the optimization of orotron show that during the guarantee of an operating current of the device of a sufficient value, it is a possibility of obtaining the output power into hundreds of watts even on the 2nd space harmonic. However, in this case essential role plays the quality of the treatment of surface TRPS: the higher it is, the shorter the length at which the maximum efficiency of device is reached and the greater its value and, therefore, the greater output power. the procedure of an increase of the length of interaction is developed in orotron with semispherocylindrical OR due to the use of the multi-focal focusing mirror.

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