ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)


turbulence

Investigation of the broadband noise-like microwave generator on multispeed nonlaminar electron beams

  The paper presents the results of theoretical and experimental studies of multispeed electron beams. Theoretical and experimental studies of the structure of such beams are considered. It is shown that turbulence forms in such electron beams. It leads to the formation of multiple bunches of space charge, which are sources of broadband noise-like fluctuations. The results of  experimental studies of small-sized laboratory model of the generator based on the principles of  formation and use of multispeed turbulent electron beams are shown.

Turbulence in microwave electronics: teoretical approaches and experimental results

A review of the current state of different theoretical approaches to the description of turbulence in electron beams and electronic devices at microwave frequencies is shown. A three types of turbulent (nonlaminar) electron beams were considered. The first type of turbulent electron beam is caused by the intersection of electronic trajectories (e.g., due to thermal velocity) and it is common to the flow of electrons at all.

Fractal geometry

The article deals with the bases of fractal geometry and fates of its creators. The biographies and the discoveries of Felix Hausdorff and Abram Besicovitch – the main characters of the great play called fractal geometry – are presented with the possible degree of detail. There is no doubt that the author and director of this play was Benoit Mandelbrot. The article presents his biography and brief descriptions of the lives of his predecessors: Henri Poincare, Maurice Gaston Julia and Pierre Gaston Jose Fatou.