E. A. Shamov - Post-graduate Student, Volgograd State Technical University. E-mail: neuro_mind@mail.ru
A. G. Shein - Dr.Sc. (Phys.-Math.), Professor, Volgograd State Technical University. E-mail: professor39@mail.ru

Microwave devices, developed about a century ago, are widely used in various areas of human activity. However, until now there remain only partially researched reasons of a particular behavior of electron streams and their noise properties, and thus there is no possibility to create devices with previously well-known characteristics and properties. For the first time the result of investigations revealed the formation of separate electron bunches in long streams with static crossed fields that define the behavior of stream and its noise properties. In the spectral composition of stream with formed geometry of bunches, the area with the amplitude of AC is exceeding the noise in multiple times and concentrated in a fairly narrow frequency range (generally less than several GHz). In this case, since the electrons between individual bunches must also almost completely miss, the noise outside of the range for real streams should be almost completely missing. When geometry of electron bunches of stream is formed, cyclotron, plasma and combined cyclotron-plasma frequency do not allow to determine maximums of AC amplitude, even partially. The maximum amplitude of AC match to precisely fundamental frequencies of bunches pass through the appropriate cross section. With increasing distance from the plane of injection stream to investigated cross section decreases frequency corresponding to the maximum amplitude of AC. This occurs for two reasons. Firstly, thanks to the process of formation of bunches, and precisely because electrons in between bunches, adjoin to the neighboring bunch. Secondly, because bunches become more distance from each other under the influence of the space charge. In the end, responsible for the appearance of a high level of broadband noise in microwave devices M-type serves stream instability caused by the influence of space-charge forces and provoking the process of formation of bunches within the stream.