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BELL SYSTEM TECHNICAL JOURNAL 



ing chapters, the practical importance of these parameters in the opera- 

 tion of traveUng-wave tubes will be discussed. 



There are other effects not encompassed by these equations. The effect 

 of transverse electron motions is small in most tubes because of the high 

 focusing fields employed; it will be discussed in a later chapter. The dif- 

 ferences between a field theory in which different fields act on different elec- 

 trons and the theory leading to (7.14)-(7.20), which apply accurately 

 only when all electrons at a given ^-position are acted on by the same field, 

 will also be discussed. 



