SPACE-CHARGE EFFECTS IN PLASMA-FILLED TRAVELING-WAVE TUBES

A theory describing the ac space charge effects in plasma-filled trave ling-wave tubes (TWT) is presented. It is shown that in the case of op eration at frequencies between the plasma frequency and the upper-hybr id frequency, the space charge forces can significantly enhance the ef ficiency. The analysis of a concrete, plasma-filled, coupled-cavity TW T shows that over a 20% bandwidth the calculated efficiency can exceed 40%. (C) 1997 American Institute of Physics.