MAGNETRON AS GENERATOR OF CENTIMETER WAVES 



195 



oscillation, equals the energy {)er cycle which is delivered to the load. This 

 amount of energy is twice that transferred in the half cycle during which the 

 spokes of space charge move against the field from positions in front of one 



ROTATING ANODE 

 POTENTIAL WAVE 



Fig. 15. — The orbits of four electrons which left the cathode in different phases, plotted 

 n a coordinate system rotating with the anode potential wave. These orbits have been 

 icalculated by the self consistent field method which includes space charge effects. In this 

 frame of reference the orbits exhibit loops whereas in a stationary frame they would more 

 nearly exhibit cusps. The dashed lines inclose the orbits of the electrons and hence de- 

 lineate the boundaries of the space charge cloud which rotates around the cathode in syn- 

 chronism with the anode potential wave. Planes of maximum retarding tangential field 

 are represented by the lines M (see Fig. 14). This figure is reproduced by courtesy of the 

 British Committee on Valve Development (CVD) and is taken from the CVD Magnetron 

 Report No. 41. 



set of alternate anode segments to similar positions in front of the adjacent 

 anode segments. 



In each spoke of the electron space charge cloud, individual electrons 

 progress from cathode to anode. The DC current, /, passed by the magne- 

 tron is made up of electrons which strike the anode from the ends of the 

 space charge spokes. Quite apart from its dependence on other parameters, 



